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The surface area of cuboid is 1372 sq cm. If it's dimmensions are the ratio 4:2:1then it's length will be

Posted by Prachi Singh 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Palak Gupta 3 years, 8 months ago

Let the length be 4x Let the breadth be 2x Let the height be x Surface area=2(lb+bh+hl) =2(8x²+2x²+4x²) =28x²=1372 so x²=49 and x=7 So length=4x=28cm breadth=2x=14cm &. height=x=7cm I hope the above solution will help you...

Khushi Kaur 3 years, 8 months ago

Given the surface area of cuboid as 1372cm2 , length are in the ratio of 4:2:1 Let the lenght, breadth and height of cuboid are 4x ,2x and x respectively. surface area of cuboid = 2(lb+bh+lh) where l= length of cube , b = breadth , h = height of cube surface area of cuboid = 2(lb+bh+lh) 1372= 2(4x*2x+2x*x+4x*x) 1372= 2(8x2+2x2+4x2) 1372= 2*14x2 1372= 28X2 1372/28 = X2 X2 = 49 // TAKING SQUARE ROOT // √X2 =√49 X = 7 length of cuboid is 4x 7 =28cm

ANSWER

Prove that the line of centres of two intersecting circles subtends equal angles at the two points of intersection

Posted by Palak Rathore 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Palak Gupta 3 years, 8 months ago

Given: Two circles with centers A and B, which intersect each other at C and D. To prove : ∠ACB=∠ADB Construction : Join AC,AD,BD and BC. Proof : In triangles ACB and ADB, we have AC=AD ...Radii of the same circle BC=BD ...Radii of the same circle AB=AB ...Common Therefore, by SSS criterion of congruence, △ACB≅△ADB ⇒∠ACB=∠ADB ...CPCT

Khushi Kaur 3 years, 8 months ago

Given : Two intersecting circles, in which OO′ is the line of centres and A and B are two points of intersection. To prove : ∠OAO′ = ∠OBO′ Construction : Join AO, BO, AO′ and BO′. Proof : In ∆AOO′ and ∆BOO′, we have AO = BO [Radii of the same circle] AO′ = BO′ [Radii of the same circle] OO′ = OO′ [Common] ∴ ∆AOO′ ≅ ∆BOO′ [SSS axiom] ⇒ ∠OAO′ = ∠OBO′ [CPCT] Hence, the line of centres of two intersecting circles subtends equal angles at the two points of intersection. Proved.Read more on Sarthaks.com - https://www.sarthaks.com/12080/prove-that-line-centres-intersecting-circles-subtends-equal-angles-points-intersection

ANSWER

In ∆ABC, D and E are the mid point of side AB and AC respectively as shown in figure find the length of DE

Posted by Amrit Saini 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Palak Gupta 3 years, 8 months ago

In Triangle ABC D is the mid-point of AB E is the mid point of AC ∴ DE||BC and DE= 1/2 BC So DE=1/2 ×8.2 DE=4.1 cm

ANSWER

Find the class mark of the classes 100 – 120

Posted by Nivedita Singh 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Vanshika Jain 3 years, 8 months ago

Class marks=(upper limit+lower limit)/2 =120+100/2=220/2=110 is the ans

Khushi Kaur 3 years, 8 months ago

Class mark = (Lower limit + Upper limit)/2 = 100 + 120/2 = 110

ANSWER

What are chords

Posted by Krish Achra? 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Saniya .. 3 years, 8 months ago

A chords is a line segment joining two points on the curve.

Suchitra Sen 3 years, 8 months ago

Chord:A line segment joining any two points on the circlee.

ANSWER

Total surface area of cuboid

Posted by I Am Jasu Bhati 3 years, 8 months ago

CBSE > Class 09 > Mathematics

3 answers

Abdul Bashit 3 years, 8 months ago

Total surface area of cuboid is 2(lb+bh+hl)

Abhishek Singh 3 years, 8 months ago

2(lb+bh+hl)

Bharat Sharma 3 years, 8 months ago

2(lb×bh×hl)

ANSWER

-+-=

Posted by Manav Thakkar 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Rimjhim Goswami 3 years, 8 months ago

+

Abhishek Singh 3 years, 8 months ago

+

ANSWER

-+-

Posted by Manav Thakkar 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Abhishek Singh 3 years, 8 months ago

+

ANSWER

Case study questions

Posted by Shrinu Rao 3 years, 8 months ago

CBSE > Class 09 > Mathematics

0 answers

ANSWER

I need all concepts of surface areas and volum

Posted by Yogesh Yogi 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Yogesh Yogi 3 years, 8 months ago

Ok

Prathamesh Kale 3 years, 8 months ago

Nahi ?

ANSWER

Find the remainder when x^4 + 3x^2 + 4x+5 is divided by x- 1/2

Posted by Dharnavi Dokka 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Akshay V.B. 3 years, 8 months ago

125/16

ANSWER

Ex 10.3

Posted by Bishal Chetry 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Niharika Sharma 3 years, 8 months ago

Draw different pairs of circles. How many points does each pair have in common? What is the maximum number of common points? Ans. From the figure, we observe that when different pairs of circles are drawn, each pair have two common points (say A and B). Maximum number of common points are two in each pair of circles. Suppose two circles C (O, ) and C (O’, ) intersect each other in three points, say A, B and C. Then A, B and C are non-collinear points. We know that: There is one and only one circle passing through three non-collinear points. Therefore, a unique circle passes through A, B and C. O’ coincides with O and A contradiction to the fact that C (O’, ) C (O, ) Our supposition is wrong. Hence two different circles cannot intersect each other at more than two points. 2. Suppose you are given a circle. Give a construction to find its centre. Ans. Steps of construction: (a) Take any three points A, B and C on the circle. (b) Join AB and BC. (c) Draw perpendicular bisector say LM of AB. (d) Draw perpendicular bisector PQ of BC. (e) Let LM and PQ intersect at the point O. Then O is the centre of the circle. Verification: O lies on the perpendicular bisector of AB. OA = OB ……….(i) O lies on the perpendicular bisector of BC. OB = OC ……….(ii) From eq. (i) and (ii), we observe that OA = OB = OC = (say) Three non-collinear points A, B and C are at equal distance from the point O inside the circle. Hence O is the centre of the circle. 3. If two circles intersect at two points, prove that their centres lie on the perpendicular bisector of the common chord. Ans. Given: Let C (O, r) and C (O’, r') be two circles intersecting at A and B. AB is the common chord. To prove: OO’ is the perpendicular bisector of the chord AB, i.e., AM = MB and OMA = OMB = Construction: Join OA, OB, O’A, O’B. Proof: In triangles OAO’ and OBO’, OA = OB [Each radius] O’A = O’B [Each radius] OO’ = OO’ [Common] OAO’ OBO’ [By SSS congruency] AOO’ = BOO’ [By CPCT] AOM = BOM (i) Now in AOB, OA = OB And AOB = OBA [Proved earlier] Also AOM = BOM [From eq.(i)] Remaining AMO = BMO Since AMO + BMO = [Linear pair] 2AMO = AMO = BMO = OM AB OO’ AB Since OM AB M is the mid-point of AB, i.e., AM = BM Hence OO’ is the perpendicular bisector of AB.

ANSWER

If two equal chords of a circle intersect within the circle prove that thesegments of one chord are equal to corresponding segments of the other chord

Posted by Ashish Kumar 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Alphonsa Jimmy 3 years, 8 months ago

Drop a perpendicular from O to both chords AB and CD In △OMP and △ONP As chords are equal, perpendicular from centre would also be equal. OM=ON OP is common. ∠OMP=∠ONP=90 o △OMP ≅ △ONP (RHS Congruence) PM=PN ......................(1) AM=BM (Perpendicular from centre bisects the chord) Similarly ,CN=DN As AB=CD AB−AM=CD−DN BM=CN .........................(2) From (1) and (2) BM−PM=CN−PN PB=PC AM=DN (Half the length of equal chords are equal) AM+PM=DN+PN AP=PD Therefore , PB=PC and AP=PD is proved.

ANSWER

An angle is 20 degree than three times the given angle. if the two angles are supplementary,then the angle are

Posted by Chetan Sangwan 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Aryan Raj 3 years, 8 months ago

Let the given angle be x ..then that required angle 3x+20 Now x+3x+20 =180 4x=180-20=160 x=160/4 = 40 So angles are 40 degree and 140 degree respectively.

ANSWER

A circular path of radius 20m is situated in a colony. Three boys Ankur, Syed and David are sitting at equal distances on its boundary each having a toy telephone in his hand to talk to each other. Find the length of the string of each phone.

Posted by Abhishek Singh 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Alphonsa Jimmy 3 years, 8 months ago

Let Ankur be represented as A, Syed as S and David as D. The boys are sitting at an equal distance. Hence, △ASD is an equilateral triangle. Let the radius of the circular park be r meters. ∴OS=r=20m. Let the length of each side of △ASD be x meters. Draw AB⊥SD ∴SB=BD= 2 1 SD= 2 x m In △ABS,∠B=90 o By Pythagoras theorem, AS 2 =AB 2 +BS 2 ∴AB 2 =AS 2 −BS 2 =x 2 −( 2 x ) 2 = 4 3x 2 ∴AB= 2 3 x m Now, AB=AO+OB OB=AB−AO OB=( 2 3 x −20) m In △OBS, OS 2 =OB 2 +SB 2 20 2 =( 2 3 x −20) 2 +( 2 x ) 2 400= 4 3 x 2 +400−2(20)( 2 3 x )+ 4 x 2 0=x 2 −20 3 x ∴x=20 3 m The length of the string of each phone is 20 3 m.

ANSWER

Calculate the value of x

Posted by Abhay Agarwal 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Khushi Kaur 3 years, 8 months ago

Find the value of X? Steps involved in finding the value of x calculator is as follows: Method 1: The required input value must be entered in the divisor and the product field. Method 2: Click the ‘SOLVE’ option to obtain the output. Method 3: The output field will present the x value or the dividend.

ANSWER

What is formula of square root

Posted by Emilal Nayak Emilal Nayak 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Khushi Kaur 3 years, 8 months ago

The square root of the number y whose square is x. The square root is denoted by √ We find the square root of a number by the following methods: i) By Prime Factorisation ii) By Long Division iii) By Repeated subtraction method

Abhishek Singh 3 years, 8 months ago

There is no formulae. There are various methods to find square root. One of the best methods is "long division method". It is used to find perfect square as well as imperfect square

ANSWER

Simplify (2√3/√3-1)-(7/√12-√5)+(2+√5/4+3√5)

Posted by World Wide Handsome💜 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Patel Het 3 years, 8 months ago

90

ANSWER

Means of ar in

Posted by Sandeep Mahanta 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Utkarsh Goyal 3 years, 8 months ago

Xxx

Abhishek Singh 3 years, 8 months ago

Sexual contact

ANSWER

ABCD is a quadrilateral in which angleABC= 73° angleC= 97° and angleD=110°. If AE||DC,BE||AD and AE intersect BD at F, find angle BEF

Posted by Bhavay Goel 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Khushi Kaur 3 years, 8 months ago

Given AE is parallel to DC and BE is parallel to AD, ∠ ABC = 73°, C = 97° To find : ∠ EBF Since AE is parallel to DC ∴ 110° + ∠ DAE = 180° (Co-interior ∠'s) Also, ∠ BEA = ∠ DCF = 97° (Corresponding B ∠'s) ⇒ ∠ BEA = 97° Now in Δ ABF, ∠ FAB + ∠ ABF + ∠ AFB = 180° (Angle Sum Property) ⇒ ∠ FAB + 73° + 97° = 180° ⇒ ∠ FAB = 180°-170° ⇒ ∠ FAB = 10° Now, AD is parallel to BE (Given) ∴ ∠ DAB + ∠ ABE = 180° ( Co-interior angles) ⇒ ∠ DAF + ∠ FAB + ∠ ABF + ∠ EBF = 180° ⇒ 70° + 10° + 73° + ∠ EBF = 180° ∠ EBF = 180°- 153° ∠ EBF = 27°

ANSWER

What is the fourmula of a2-b2

Posted by Tanmay Saini 3 years, 8 months ago

CBSE > Class 09 > Mathematics

4 answers

Abhishek Singh 3 years, 8 months ago

(a+b)(a-b)

K S 3 years, 8 months ago

(a+b)(a-b)

Naman Kumar 3 years, 8 months ago

identity a2 – b2 = (a + b)(a – b)

Bhavya Kumari 3 years, 8 months ago

(a+b)(a-b)

ANSWER

Let's have ad dance

Posted by Pranam Kala 3 years, 8 months ago

CBSE > Class 09 > Mathematics

0 answers

ANSWER

80/hour convert metre per second

Posted by Priya . 3 years, 8 months ago

CBSE > Class 09 > Mathematics

3 answers

Abhishek Singh 3 years, 8 months ago

22.22m/s

Aditi Patil 3 years, 8 months ago

22.22 m/s

Pranam Kala 3 years, 8 months ago

Multiple by 1000/3600

ANSWER

In ∆ ABC, D and E are the midpoints of the sides AB and AC respectively. If DE is 5 cm, find the measure of the side BC.

Posted by Nihal Shankar 3 years, 8 months ago

CBSE > Class 09 > Mathematics

3 answers

Bhavya Kumari 3 years, 8 months ago

BC=10cm because of mid point theorem in which DC is half and parallel to BC

Kripa Daga 3 years, 8 months ago

10 cm

Himanshu Gupta 3 years, 8 months ago

According to the midpoint theorem DE =1\2 of BC 5 = 1\2 of BC BC = 5 * 2 Hence, BC = 10

ANSWER

What is incentre

Posted by Ankush Ranjan 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Bhavya Kumari 3 years, 8 months ago

The centre of circle inscribed in triangle

Gurtej Singh Bedi 2959 3 years, 8 months ago

the centre of the incircle of a triangle or other figure.

ANSWER

What is the percentage increase in dispensaries from 1951 to 2015 Dispensaries |29274|29709|29957

Posted by Sherap Yt 3 years, 8 months ago

CBSE > Class 09 > Mathematics

0 answers

ANSWER

a-b-a^2+b^2

Posted by Neha Yadav 3 years, 8 months ago

CBSE > Class 09 > Mathematics

2 answers

Rimjhim Goswami 3 years, 8 months ago

(a-b)(a+b)(a-b)

Priyanka Nautiyal 3 years, 8 months ago

A-b

ANSWER

Write the zero of polynomial p(x)=3x^2-1

Posted by Anshu Kumari 3 years, 8 months ago

CBSE > Class 09 > Mathematics

5 answers

Adarsh Patil 3 years, 8 months ago

Root -1/3

T.Nikhil Chowdary Nikhil Chowdary 3 years, 8 months ago

NIKHIL CHOWDARY is crrt

T.Nikhil Chowdary Nikhil Chowdary 3 years, 8 months ago

-1

Anant Vats 3 years, 8 months ago

Ghj

Sasjasee Sasjasee 3 years, 8 months ago

7777

ANSWER

Puncuate prospero eas a duck of millan in the kingdom of nepal

Posted by Sujal Mane 3 years, 8 months ago

CBSE > Class 09 > Mathematics

0 answers

ANSWER

Evaluate 16 3/4

Posted by Mayur Sonkar 3 years, 8 months ago

CBSE > Class 09 > Mathematics

1 answers

Kripa Daga 3 years, 8 months ago

16*3/4 •4*3 •12

ANSWER

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