# FRANK Solutions for Class 9 Maths Chapter 12 - Isosceles Triangle

Practise Frank Solutions for ICSE Class 9 Mathematics Chapter 12 Isosceles Triangle to revise the SAS criteria of triangles.  Learn to use the Angle-Side-Angle Criterion of Triangle to prove that a given triangle is an isosceles triangle. Go through the Maths solutions to grasp the ways the properties of triangle and angle can be used to use isosceles triangle-based problems.

Also, learn the steps to use the property of vertically opposite angles to provide proofs in a given problem based on an isosceles triangle. Apart for our Frank textbook solutions, review chapter concepts using our ICSE Class 9 Maths video lessons, online practice tests, and other study materials.

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## Chapter 12 - Isosceles Triangle Exercise Ex. 12.1

Question 1 Solution 1 Question 2 Solution 2 Question 3 Solution 3 Question 4(a)

Find the interior angles of the following triangles: Solution 4(a)  Question 4(b)

Find the interior angles of the following triangles: Solution 4(b)  Question 4(c)

Find the interior angles of the following triangles: Solution 4(c)  Question 4(d)

Find the interior angles of the following triangles: Solution 4(d)  Question 5 Solution 5 Question 6 Solution 6 Question 7 Solution 7 Question 8 Solution 8 Question 9 Solution 9 Question 10 Solution 10 Question 11 Solution 11 Question 12 Solution 12 Question 13 Solution 13 Question 14 Solution 14 Question 15 Solution 15 Question 16 Solution 16 Question 17 Solution 17 Question 18 Solution 18 Question 19 Solution 19 Question 20

In the given figure, D and E are points on AB and AC respectively. AE and CD intersect at P such that AP = CP. If BAE = BCD, prove that DBDE is isosceles. Solution 20  Question 21

In DPQR as shown, PQS = RQS and QS PR. Find the value of x and y, if PQ = 3x + 1; QR = 5y - 2; PS = x + 1 and SR = y + 2. Solution 21  Question 22(a)

In the given figure :

if PQS = 60o,

a. find QPR.

b. show that PQ = PS = QS = SR

Solution 22(a) Question 23

In the give figure, if DPQR is an isosceles triangle, prove that: QSR = exterior PRT. Solution 23  Question 24

In the given figure, if DABC is an isosceles triangle and PAC = 110o, find the base angle and vertex angle of the DABC. Solution 24  ### STUDY RESOURCES

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