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In geometry, Heron's formula (sometimes called Hero's formula), named after Hero of Alexandria, gives the area of a triangle when the length of all three sides are known. Unlike other triangle area formulae, there is no need to calculate angles or other distances in the triangle first.

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Theorem 6.5 and 6.6

Posted by Ujjwal Tiwari 5 years ago

CBSE > Class 09 > Mathematics

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Unit 10 Exercise 10.2 solved

Posted by Tanuj Sharma 5 years ago

CBSE > Class 09 > Mathematics

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Snehasish Mohanty 5 years ago

1. Recall that two circles are congruent if they have the same radii. Prove that equal chords of congruent circles subtend equal angles at their centres. Solution: To recall, a circle is a collection of points whose every point is equidistant from its centre. So, two circles can be congruent only when the distance of every point of both the circles are equal from the centre. Ncert solutions class 9 chapter 10-1 For the second part of the question, it is given that AB = CD i.e. two equal chords. Now, it is to be proven that angle AOB is equal to angle COD. Proof: Consider the triangles ΔAOB and ΔCOD, OA = OC and OB = OD (Since they are the radii of the circle) AB = CD (As given in the question) So, by SSS congruency, ΔAOB ΔCOD ∴ By CPCT we have, AOB = COD. (Hence proved). 2. Prove that if chords of congruent circles subtend equal angles at their centres, then the chords are equal. Solution: Consider the following diagram- Ncert solutions class 9 chapter 10-2 Here, it is given that AOB = COD i.e. they are equal angles. Now, we will have to prove that the line segments AB and CD are equal i.e. AB = CD. Proof: In triangles AOB and COD, AOB = COD (as given in the question) OA = OC and OB = OD (these are the radii of the circle) So, by SAS congruency, ΔAOB ΔCOD. ∴ By the rule of CPCT, we have AB = CD. (Hence proved)

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Shreekanth Cm 5 years ago

Woooooowwwwww

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Smallest positive integer?

Posted by Shreyansh Tripathi 5 years ago

CBSE > Class 09 > Mathematics

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Vidhi Verma 5 years ago

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Vanshika Jain 5 years ago

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Anamika Chauhan 5 years ago

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Shreyansh Tripathi 5 years ago

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Rationalize the denominator of 3 2 3 2   .

Posted by Ranvir Singh 5 years ago

CBSE > Class 09 > Mathematics

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Harsh Raj 5 years ago

write the from of p/q 0.57

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(Motivate) Two triangle are congruent if any two sides and the included angle of one triangle is equal of the other triangle (SAS Congruence )

Posted by Susri Namrata Deep 5 years ago

CBSE > Class 09 > Mathematics

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Roopak Kumar 5 years ago

When two angles and side included in between these angles of one triangle are same as another one, both these triangle are Congruent. This criteria of congruency is knows as ASA criterion as a side included between two angles are all same.

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a milkman is appointed to serve a glass of milk to every child of children who he was suggested to choose whether a cuboid shaped glass of dimensions 5cm 2cm of cylindrical glass of diameter 3.5 cm and height 10 cm code for certain student everyday. 1.What should be his choice of Glass by the point of view of health of growing children 2.How much quantity of milk in litre is required if you want to serve in Cuba glass 3.How much quantity of milk in litre is required if we want to serve in cylindrical glass 4.How much amount of milk is more than other in cubic centimetre 5.If he has chosen container of bigger volume what value is depicted by them

Posted by Krupa Devar 5 years ago

CBSE > Class 09 > Mathematics

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Find five rational number between 3

Posted by Raj Sharma 5 years ago

CBSE > Class 09 > Mathematics

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आदित्य कुमार झा 5 years ago

Priyanshu bro correct

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Priyanshu Bro 5 years ago

31/50,32/50,33/50,34/50,35/50.

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Raj Sharma 5 years ago

012

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Prove that if the two arms of an angle are perpendicular to the two arms of another angle, then the angles are either equal or supplementary.

Posted by Vishal Dhakar 5 years ago

CBSE > Class 09 > Mathematics

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In the adjacent figure AB||CD;CD||EF

Posted by Bijender Simar 5 years ago

CBSE > Class 09 > Mathematics

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The difference between upper limit and lower limit is called

Posted by Pooja Parashar 5 years ago

CBSE > Class 09 > Mathematics

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Pooja Verma 5 years ago

Range

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Adithi K.Iyer 5 years ago

The difference between upper limit and lower limit is called RANGE

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Avika Gupta 5 years ago

Class interval

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In figer angles X=62 angle xyz=54 if Yo and ZO are the bisectors of ∆xyz and ∆xzy

Posted by Parul Prajapati 5 years ago

CBSE > Class 09 > Mathematics

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Prince Yadav 5 years ago

A+B+C=1

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What does the bisectors of the angles of a parallelogram encloses?

Posted by Payal Jaiswal 5 years ago

CBSE > Class 09 > Mathematics

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Payal Jaiswal 5 years ago

As x+y=180o⇒2x+2y=90o ⇒∠DPA=90o=∠SPQ (vertically opp) ∠SRQ=90o=∠PSR=∠PQR Also In △ASB′y′&′B′ are distinction ∴ As is d if from BS hence PQRS is A rectangle.

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Parul Prajapati 5 years ago

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Ex. 7.2 Q-8

Posted by Ujjwal Tiwari 5 years ago

CBSE > Class 09 > Mathematics

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ᵐⁱˢˢ Lucid Dream 5 years ago

ՏO Tᕼᗴ ᑫᑌᗴՏTIOᑎ ᗯᗩՏ - Show that the angles of an equilateral triangle are 60° each. Solution: Let ABC be an equilateral triangle Here, BC = AC = AB (Since the length of all sides is same) ⇒ A = B =C (Sides opposite to the equal angles are equal.) Also, we know that A+B+C = 180° ⇒ 3A = 180° ⇒ A = 60° ∴ A = B = C = 60° So, the angles of an equilateral triangle are always 60° each.

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6.3

Posted by Kulvinder Singh 5 years ago

CBSE > Class 09 > Mathematics