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35 votes
Find the shaded area (round answer to 3 sig figs).

Find the shaded area (round answer to 3 sig figs).-example-1
User Tuure Laurinolli
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1 Answer

24 votes
24 votes

1. Let us find the area of the sector:


\begin{gathered} (\theta)/(360)\cdot\pi\cdot r^2\text{ (Area of a sector formula)} \\ (85)/(360)\cdot\pi\cdot(12\operatorname{cm})^2\text{ (Replacing)} \\ (85)/(360)\cdot\pi\cdot144cm^2\text{ (Raising 12 to the power of 2)} \\ 0.236\cdot\pi\cdot144cm^2\text{ (Dividing)} \\ 106.814cm^2\text{ (Multiplying)} \end{gathered}

2. The area of the triangle would be:


\begin{gathered} At=(1)/(2)\cdot ab\cdot\sin (\theta)\text{ (Area of a non right-angled triangle)} \\ At=(1)/(2)\cdot(12)\cdot(12)\cdot\sin (85)\text{ (Replacing)} \\ At=71.726cm^2 \end{gathered}

3. Subtracting the area of the triangle from the area of the sector, we have:

106.814 cm^2 - 71.726 cm^2 = 35.088 cm^2

The answer is 35.088 cm^2

User DannyMeister
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