Question

The length of two sides of an isosceles triangle are 9 cm and 20 cm. What is the perimeter of the triangle?

• A. 49 cm
• B. 27 cm
• C. 60 cm
• D. 38 cm

Answer 1

The correct option is A 49 cm

Third side can be either 20 cm or 9 cm,because as it is an isoceles triangle two side length must be equal.

Now, as we know that sum of two sides of a triangle must be greater than third side.
So if we take third side as 9 cm, then 9cm + 9cm < 20cm .

Hence, third side must be 20 cm.
So, perimeter = ( 20 + 20 + 9) = 49 cm.
Hence, Option A is correct.