Calculate the area of the isosceles triangle with length of equal sides 5 cm and the third side 8 cm.

Correct option is A

Given:

Isosceles triangle with equal sides = 5 cm, third side = 8 cm

Need to find area.

Formula Used:

Semi-perimeter:

s = $$\frac{a + b + c}{2}$$​​

Area of triangle:

= $$\sqrt{s(s-a)(s-b)(s-c)}$$​​

Solution:

s = $$\frac{5 + 5 + 8}{2}$$​ = 9

Area of triangle; 

= $$\sqrt{9(9-5)(9-5)(9-8)}$$​​

= $$\sqrt{9 \times 4 \times 4 \times 1}$$​​

= $$\sqrt{144}$$ = 12 cm²