Question

Find the area of the shaded region. Use 3.14 for π as necessary.The circle centered on point A, and has a radius of 5 cm, is shaded. BC is a diameter of the circle. Point D is on the cicle, such that line AD is perpendicular to line BC. Triangle BCD is not shaded.A. 132 cm²B. 53.5 cm²C. 26.8 cm²D. 17.1 cm²

Answer 1

Given

radius = 5 cm

To get the area of the shaded region, get the difference between the area of the circle, and the area of the triangle

We have the following

`\begin{gathered} A_{\text{circle}}=\pi r^2 \\ A_{\text{circle}}=(3.14)(5\text{ cm})^2 \\ A_{\text{circle}}=(3.14)(25\text{ cm}^2) \\ A_{\text{circle}}=78.5\text{ cm}^2 \\ \\ A_{\text{triangle}}=(1)/(2)bh \\ A_{\text{triangle}}=(1)/(2)(10\text{ cm})(5\text{ cm})\text{ *the base is twice the radius} \\ A_{\text{triangle}}=25\text{ cm}^2 \\ \\ A_{\text{shaded area}}=A_{\text{circle}}-A_{\text{triangle}} \\ A_{\text{shaded area}}=78.5\text{ cm}^2-25\text{ cm}^2 \\ A_{\text{shaded area}}=53.5\text{ cm}^2 \end{gathered}`

Therefore, the area of the shaded region is 53.5 cm².