Question

0,4B is a sector of a circle with radius 12cm . If angle AOB =30 degree . find the area between arc AB and chord AB​

Answer 1

ANSWER

Since OA=OB, so ΔOAB is an equilateral triangle, therefore, let

∠A=∠B=x

Since the sum of the angles of a triangle is 180∘.

x+x+60∘=180∘

2x=180∘−60∘

2x=120∘

x=60∘

The area of sector OAB is,

A=πr2360θ

=722×12×12×36060

=75.42cm2

The area of ΔOAB is,

A=43(side)2

=43×12×12

=62.28cm2

The difference in the area is,

A=75.42−62.28

A=13.14cm2