Question

The area of an isosceles triangle, each of whose equal sides is $13cm$ and whose base is $24cm$ is

• A. $60c{m}^2$
• B. $55c{m}^2$
• C. $50c{m}^2$
• D. $40c{m}^2$

Answer 1

The correct option is

B

$60c{m}^2$

Let the equal sides of the isosceles triangles be $a$ cm and the base be of $b$ cm.

Then according to the problem, $a=13$ and $b=24$.

Now the area of the isosceles triangle will be

$=\frac{1}{2}\times b\times \sqrt{a^2-{\left(\frac{b}{2}\right)}^2}$

$=\frac{1}{2}\times 24\times \sqrt{{13}^2-{12}^2}$

$=12\times 5=60$.

So the area of the isosceles triangles be $60$ cm${}^2$.