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40 votes
Fond the radius of this sector to the nearest tenth

Fond the radius of this sector to the nearest tenth-example-1
User Fatih Mar
by
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1 Answer

14 votes
14 votes

To determine the radius of the circle using the portion shown in the picture you have to use the formula to calculate the arc length of the segment.


s=2\pi r((\theta)/(360))

Where

s is the arc length

r is the radius

π is the number pi

θ is the central angle

For the portion of the circle shown in the picture, the arc length is s=15cm and the angle is θ=27º

The first step you have to write the formula in terms of r:


s=2\pi r((\theta)/(360º))

-Divide both sides by 2π


\begin{gathered} (s)/(2\pi)=(2\pi)/(2\pi)r((\theta)/(360)) \\ (s)/(2\pi)=r((\theta)/(360)) \end{gathered}

-Multiply both sides of the expression by the reciprocal fraction of (θ/360), which is (360/θ)


(s)/(2\pi)\cdot(360)/(\theta)=r

Next, replace the formula with the given arc length and angle and calculate the radius:


\begin{gathered} r=(s)/(2\pi)\cdot(360)/(\theta) \\ r=(15)/(2pi)\cdot(360)/(27) \\ r=31.8\operatorname{cm} \end{gathered}

The radius has a measure of 31.8cm

User Aro
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