Find the area of an equilateral triangle with a side length of 10 cm.

Correct option is B

Given :

Side of equilateral triangle  = 10 cm

Formula Used :
​$$\text{Area of equilateral triangle} = \frac{\sqrt{3}}{4} a^2$$
where a= Side of equilateral triangle 
Solution :

​$$\text{Area} = \frac{\sqrt{3}}{4} \times 10^2$$​​
= $$\frac{\sqrt{3}}{4} \times 100$$​​
​$$= 25\sqrt{3}\text{cm}^2$$​​