Rabeya drew an eq

Given: Length of side of equilateral triangle = 21 cm

Area of the colored portion = Area of the circum circle - Area of ∆BCD

Height of equilateral triangle

The centroid of equilateral triangle is at A and lies on height BE.

⇒ BA = 7√3 cm

So, the radius of the circum circle of this triangle = 7√3 cm.

∵ Area of a circle = πr²

Area of the circum circle

⇒ Area of the circum circle = 462 cm²

We know that

Area of a equilateral triangle where a is the side of it.

⇒ Area of ∆BCD = 190.96cm²

Now, Area of the colored portion = 462 – 190.96

⇒ Area of the colored portion = 271.04 cm²