Answer:
231.48 cm²
Step-by-step explanation:
Formulae
Area of a rectangle = width × length
Area of a triangle = 1/2 × base × height
Area of a semicircle = 1/2 πr²
To find the shaded area:
Find the area of the rectangle. Subtract the area of the semicircle from the rectangle. Add this to the area of the triangle.
Area of the rectangle:
= 12 x 21
= 252 cm²
Area of the semicircle:
= 1/2 π(12 ÷ 2)²
= 1/2 · 3.14 · 6²
= 1/2 · 3.14 · 36
= 56.52 cm²
Area of the triangle:
= 1/2 x 6 x 12
= 36 cm²
Shaded area:
= area of rectangle - area of semicircle + area of triangle
= 252 - 56.52 + 36
= 194.48 + 36
= 231.48 cm²
