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Show that sum of angles(ABC)of a triangle is 180°

Posted by Daksh Arora 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 5 years, 4 months ago

In order to prove that the sum of angles of a triangle is 180, you must know the theorems of angles of a triangle.

We know that, alternate interior angles are of equal magnitude.

This'll help us get the answer. Let us assume a triangle ABC. Now we have to substitute the angles.

∠PAB + ∠BAC + ∠CAQ = 180°. where PQ line parallel to side BC touching vertex A.

∠PAB = ∠ABC & ∠CAQ = ∠ACB BECAUSE alternate interior angles are congruent..

Hence we get, ∠ABC + ∠BAC + ∠ACB = 180° [Proved]

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Probility

Posted by Punita Raja Piush 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Ayush Tiwari 5 years, 4 months ago

It's Probability

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How to find rational numbers between two fractions

Posted by Kavi Pavi 5 years, 4 months ago

CBSE > Class 09 > Mathematics

4 answers

Shehrebanu .... 5 years, 4 months ago

A method other than equaling denominators is to add 1 to how much rational no. you want to find..........and then convert the denominator according to the sum we got by adding 1...... ..and then write the rational no. between the two no. you got.......and that you got the answer ☺

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Arjun Prabhu V.K 5 years, 4 months ago

Thanks

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Sreya Dutta 5 years, 4 months ago

First do the lcm of denominators.. Then convert the fraction to equivalent fractions containing the changed denominators.. After having same denominators.. Write fractions between those changed fractions. Ok?

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Namish Jindal 5 years, 4 months ago

Pata nahi

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Ex-4.3 ka 5 question number ka Answer

Posted by Nidhi Singh 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Ash Greninja 5 years, 4 months ago

For Fig. 4. 6 (i) y = x (ii) x + y = 0 (iii) y = 2x (iv) 2 + 3y = 7x Solution: The points given in the figure 4.6 are (0,0), (-1,1), (1,-1) Substituting the values for x and y from these points in the equations, we get, (i) y = x (0,0) ⟹ 0 = 0 (-1, 1) ⟹ -1≠1 --------------------------- equation not satisfied (1, -1) ⟹ 1≠ -1 --------------------------- equation not satisfied (ii) x + y = 0 (0,0) ⟹ 0 + 0 = 0 (-1, 1) ⟹ -1+1= 0 (1, -1) ⟹ 1+ (-1)=0 (iii) y = 2x (0,0) ⟹ 0 = 2× 0 0 = 0 (-1, 1) ⟹ 1= 2×(-1) 1 ≠ -2 --------------------------- equation not satisfied (1, -1) ⟹ -1=2×1 -1≠2 --------------------------- equation not satisfied (iv) 2 + 3y = 7x (0,0) ⟹ 2+(3×0) = 7× 0 2 ≠ 0 --------------------------- equation not satisfied (-1, 1) ⟹ 2+(3×1) = 7× -1 5 ≠ -7 --------------------------- equation not satisfied (1, -1) ⟹ 2+(3×-1)= 7× 1 -1≠ 7 --------------------------- equation not satisfied Since, only equation x + y = 0 satisfies all the points, the equation whose graphs are given in Fig. 4.6 is x + y = 0 For Fig. 4. 7 (i) y = x + 2 (ii) y = x – 2 (iii) y = –x + 2 (iv) x + 2y = 6 Solution: The points given in the figure 4.7 are (0,2), (2,0), (-1,3) Substituting the values for x and y from these points in the equations, we get, (i) y = x + 2 (0,2) ⟹ 2 = 0+2 2 = 2 (2, 0) ⟹ 0= 2+2 0≠4 --------------------------- equation not satisfied (-1, 3) ⟹ 3= -1+2 3≠1 --------------------------- equation not satisfied (ii) y = x – 2 (0,2) ⟹ 2 = 0 –2 2 ≠ – 2 --------------------------- equation not satisfied (2, 0) ⟹ 0= 2–2 0= 0 (-1, 3) ⟹ 3= –1–2 3≠ –3 --------------------------- equation not satisfied (iii) y = –x + 2 (0,2) ⟹ 2 = -0+2 2 = 2 (2, 0) ⟹ 0 = -2+2 0=0 (-1, 3) ⟹ 3= -(-1)+2 3=3 (iv) x + 2y = 6 (0,2) ⟹ 0+(2× 2) = 6 4 ≠ 6 --------------------------- equation not satisfied (2, 0) ⟹ 2+(2× 0) = 6 2 ≠ 64 --------------------------- equation not satisfied (-1, 3) ⟹ -1+(2× 3) = 6 5≠6 --------------------------- equation not satisfied Since, only equation y = –x + 2 satisfies all the points, the equation whose graphs are given in Fig. 4.7 is y = –x + 2.

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Ex-4.3 ka 5 question number..

Posted by Nidhi Singh 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Shehrebanu .... 5 years, 4 months ago

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Entire concept of roots

Posted by Naveen Jain 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Alok Gupta 5 years, 4 months ago

The root of a number x is another number, which when multiplied by itself a given number of times, equals x. For example the second root of 9 is 3, because 3x3 = 9. The second root is usually called the square root. The third root is usually called the cube root.

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Ch:3 Coordinate Geometry Find the value of x and y if : i. (x+3,5)=(5,y) ii. (2,2y-3)=(x,7)

Posted by Mufeedha S 5 years, 4 months ago

CBSE > Class 09 > Mathematics

2 answers

Gaurav Seth 5 years, 4 months ago

A n s w e r:

x = 2 , y = 5

S t e p-b y-s t e p e x p l a n a t i o n:

x = 2

2y-3 = 7

2y = 10

y = 5

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Mufeedha S 5 years, 4 months ago

with explaination

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Difference between axiom and theriom

Posted by Sachchidanand 9119 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Gaurav Seth 5 years, 4 months ago

• The axiom is a statement which is self evident.

But,a theorem is a statement which is not self evident.

• An axiom cannot be proven by any kind of mathematical representation.

But, a theorem can be proved by mathematical representation.

• A theorem can be proved or derived from the axioms.

But,axioms cannot be proven or derived by the theorems.

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In a triangle ABC, PQ is parallel to BC and angle B nd angle C are equal . If angle A is 50° then find angle PQC?

Posted by Garima Chaudhary 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Silviya Shrivastav 5 years, 4 months ago

I hope you will be able to make the diagram: Let the Angles be =x In∆ABC x+x+50°=180°(Angle Sum Property) 2x+50 =180° 2x=180°-50° 2x=130 x=130°/2 x=65° PQ||BC Angle C+AngleQ=180°(co-interior angle) 65°+Angle PQC=180° AnglePQC=180°-65° PQC=115° HOPE IT HELPS!!

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What is the value ofπ

Posted by Harsh Gupta 5 years, 4 months ago

CBSE > Class 09 > Mathematics

5 answers

Mahira Srivastava 5 years, 4 months ago

Its 22/4 or 3.14 Hope its helps you !

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Agent Nobody 5 years, 4 months ago

22/7

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Garima Chaudhary 5 years, 4 months ago

3.14 or 22/7

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Cm| Black Bolt 5 years, 4 months ago

22/7 (Fraction Form) 3.14 (Decimal Form) Hope this helps you

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Meenu Gupta 5 years, 4 months ago

The value can be 22/7 or 3.14

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53+62

Posted by Azhar Mulla 5 years, 4 months ago

CBSE > Class 09 > Mathematics

3 answers

Mahira Srivastava 5 years, 4 months ago

Its 115

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Meenu Gupta 5 years, 4 months ago

Answer is 115

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Cm| Black Bolt 5 years, 4 months ago

The answer is 115

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2x square - 9x + 4

Posted by Femely Shaji 5 years, 4 months ago

CBSE > Class 09 > Mathematics

2 answers

Yogita Ingle 5 years, 4 months ago

2x² - 9x + 4
= 2x² - 8x - x + 4

= 2x ( x - 4) - 1 ( x - 4)

= (x - 4) (2x - 1)

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Femely Shaji 5 years, 4 months ago

Step by step plzzz

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if 2 is a zero of the polynomial p (x) =2x^2 - 3x + 7a find value of a

Posted by Yagneswar Gorriparthi 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Yogita Ingle 5 years, 4 months ago

Given,

p(x) = 2x²-3x+7a

2 is the zero of the polynomial

So, substitution

p(2) = 0

p(2) = 2(2)² - 3x + 7a

0 = 2(4)-3(2)+7a

0 = 8-6+7a

0 = 2+7a

-2 = 7a

-2/7 = a

The value of a is -2/7

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The probability of an impossible event is a) 1. b)-1. c)0. d)2

Posted by Vishal Kumar 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Mahira Srivastava 5 years, 4 months ago

Its zero !

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Mean of prime number between 20al and 30 is a)25. b)20. c)30 d)26

Posted by Vishal Kumar 5 years, 4 months ago

CBSE > Class 09 > Mathematics

2 answers

Roshan Chand 5 years, 4 months ago

Mean is the sum of terms or numbers / no of terms 23 + 29 / 2 = 52 / 2 = 26 So the correct answer is d)26

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Roshan Chand 5 years, 4 months ago

Mean is sum of terms or numbers/ no of terms 20 + 30 / 2 = 50 / 2 = 25 So the answer is a)25

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The class mark for the class interval 40-60 is a) 40. b) 60. c)50. d)70

Posted by Vishal Kumar 5 years, 4 months ago

CBSE > Class 09 > Mathematics

3 answers

Meenu Gupta 5 years, 4 months ago

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Mahira Srivastava 5 years, 4 months ago

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Yogita Ingle 5 years, 4 months ago

Given class interval (40-60)

Lower limit = 40

Upper limit = 60

Class mark = (40 + 60)/2
= 100/2

= 50

Therefore, Class mark of the class interval 40-60 is 50.

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A park is in the shape of a quardilateral ABCD ,has angle C as 90degrees and ab is 9 bc is 12 cd is 5m and ad 8 m .how much area does it occupy

Posted by Ramohan Maddipati 5 years, 4 months ago

CBSE > Class 09 > Mathematics

1 answers

Gaurav Seth 5 years, 4 months ago

Given a quadrilateral ABCD in which ∠C = 90º, AB = 9 m, BC = 12 m, CD = 5 m & AD = 8 m.

Join the diagonal BD which divides quadrilateral ABCD in two triangles i.e ∆BCD & ∆ABD.

In ΔBCD,
By applying Pythagoras Theorem

BD²=BC² +CD²

BD²= 12²+ 5²= 144+25

BD²= 169
BD = √169= 13m

∆BCD is a right angled triangle.

Area of ΔBCD = 1/2 ×base× height

=1/2× 5 × 12= 30 m²

For ∆ABD,
Let a= 9m, b= 8m, c=13m

Now,
Semi perimeter of ΔABD,(s) = (a+b+c) /2

s=(8 + 9 + 13)/2 m
= 30/2 m = 15 m

s = 15m

Using heron’s formula,
Area of ΔABD = √s (s-a) (s-b) (s-c)

= √15(15 – 9) (15 – 9) (15 – 13)

= √15 × 6 × 7× 2
=√5×3×3×2×7×2
=3×2√35
= 6√35= 6× 5.92

[ √6= 5.92..]
= 35.52m² (approx)

Area of quadrilateral ABCD = Area of ΔBCD + Area of ΔABD
= 30+ 35.5= 65.5 m²

Hence, area of the park is 65.5m²