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20 votes
Please round to the nearest tenth.The area of the shaded region = square cm

User Remco Te Wierik
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1 Answer

26 votes
26 votes

To answer this question we need:

1. Find the area of the square.

2. Find the diameter of the circle. This is the diagonal of the square.

3. Find the half of the diameter, and then solve for the area of the circle.

4. Subtract the area of the square from the area of the circle.

Then, we have:

Area of the square

The area of the square is:


A_{\text{square}}=s^2=(6\operatorname{cm})^2=36\operatorname{cm}^2

Diameter of the circle (diagonal of the square)

We can use the Pythagorean Theorem. We have a right triangle.


d^2=(6\operatorname{cm})^2+(6\operatorname{cm})^2=36\operatorname{cm}+36\operatorname{cm}=72\operatorname{cm}^2

Extracting the square root to both sides of the equation:


\sqrt[]{d^2}=\sqrt[]{72\operatorname{cm}^2}\Rightarrow d=\sqrt[]{2^2\cdot2\cdot3^2}=2\cdot3\cdot\sqrt[]{2}=6\cdot\sqrt[]{2}\Rightarrow d=6\cdot\sqrt[]{2}

The radius of the circle is, therefore:


r=(d)/(2)=\frac{6\cdot\sqrt[]{2}}{2}=3\cdot\sqrt[]{2}

Area of the circle

It is given by:


A_{\text{circle}}=\pi\cdot r^2=\pi\cdot(3\cdot\sqrt[]{2})^2=\pi\cdot3^2\cdot2=\pi\cdot18=18\pi\approx56.5486677646

Hence, the shaded area is, then:


A_{\text{shadedarea}}=A_{\text{circle}}-A_{\text{square}}=56.5486677646\operatorname{cm}-36\operatorname{cm}^2=20.5486677646

In summary, the shaded area is equal to, approximately, 20.5 sq. centimeters.

Please round to the nearest tenth.The area of the shaded region = square cm-example-1
User KennyHo
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3.4k points