Question

The area of isosceles triangle is 20cm^2.If the base is 20cm,then the length of each equal side is a)4√26cm b)2√26cm c)4√6cm d)2√6cm

Answer 1

Answer:

B) 2√26cm

first find h

which is equal to 2 cm

then by Pythagoras theorem solve

Answer 2

Given:

The area of isosceles triangle is 20cm^2.

To find:

If the base is 20cm,then the length of each equal side is

Solution:

From given, we have,

The area of the isosceles triangle is 20 cm^2.

A = 20 cm²

The base of the isosceles triangle is 20 cm.

b = 20 cm

The formula for calculating the area of the isosceles triangle is,

A = bh/2

where b is the base and h is the height of the isosceles triangle.

Let "a" be the length of the equal sides of the isosceles triangle.

The formula for calculating the length of each equal side is,

$a=\dfrac{1}{2}\sqrt{b^2+16(\dfrac{A}{b})^2}$

substitute the given values in the above equation.

a = 1/2 √ [20² + 16(20/20)²]

a = 1/2 √ [400 + 16 (1)]

a = 1/2 √ 416

a = √ 104

a = 2√26 cm

Therefore, option b)2√26cm is correct.