RS Aggarwal & V Aggarwal - Mathematics

Book: RS Aggarwal & V Aggarwal - Mathematics

Chapter: 7. Areas

Subject: Mathematics - Class 9th

Q. No. 8 of Formative Assessment (Unit Test)

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8

An isosceles triangle has perimeter 30cm and each of its equal sides is 12cm. Find the area of the triangle.

It is given in the question that,

Equal sides of isosceles triangle = a = b = 12 cm


Also, perimeter = 30 cm


We know that perimeter of triangle = Sum of all sides


(a + b + c) = 30 cm


12 + 12 + c = 30


24 + c = 30


c = 30 – 24


= 6 cm


Hence, s =


s =


s = 15 cm


Area of triangle =


=


=


= 9 cm2


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