Answer:
K = (1/2)r^2(sin(θ) +θ)
Explanation:
The area of the triangle to the left is ...
A1 = (1/2)r^2·sin(180°-θ) = (1/2)r^2·sin(θ)
The area of the sector to the right is ...
A2 = (1/2)r^2θ
so the total area of the blue shaded region is ...
K = A1 + A2 = (1/2)r^2·sin(θ) + (1/2)r^2·θ
K = (1/2)r^2(sin(θ) +θ)