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In circle E, mangle, F, E, G, equals, 50, degrees∠FEG=50 ∘ and the area of shaded sector = start fraction, 5, divided by, 4, end fraction, pi 4/5 π. Find the length of arc, FG ⌢ . Express your answer as a fraction times piπ

User Johnjo
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1 Answer

5 votes

The length of the arc FG is
\( (1)/(3)\pi \).

In a circle, the area of a sector can be related to the area of the whole circle using the formula:


\[ \text{Area of sector} = \left( \frac{\text{measure of central angle}}{360^\circ} \right) * \pi r^2 \]

where r is the radius of the circle.

In this case, you are given that
\( \angle FEG = 50^\circ \) and the area of the shaded sector is
\( (5)/(4)\pi \). Let r be the radius of the circle.


\[ \text{Area of sector} = (50^\circ)/(360^\circ) * \pi r^2 = (5)/(4)\pi \]

Now, solve for r :


\[ (50)/(360) * \pi r^2 = (5)/(4)\pi \]

Multiply both sides by
\( (360)/(50) \) to solve for
\( r^2 \):


\[ \pi r^2 = (5)/(4) * (360)/(50) * \pi \]

Simplify:


\[ r^2 = (9)/(2) \]

Now, find the length of the arc FG. The formula for the length of an arc, given the central angle in degrees
(\( \theta \)) and the radius r, is:


\[ \text{Arc Length} = \left( (\theta)/(360^\circ) \right) * 2\pi r \]

In this case,
\( \theta = 50^\circ \) and
\( r^2 = (9)/(2) \), so
\( r = \sqrt{(9)/(2)} \).


\[ \text{Arc Length} = (50)/(360) * 2\pi \sqrt{(9)/(2)} \]

Simplify:


\[ \text{Arc Length} = (1)/(9) \pi √(18) \]

Expressing this in the form of a fraction times
\( \pi \):


\[ \text{Arc Length} = (1)/(9) * 3\pi = (1)/(3)\pi \]

Therefore, the length of the arc FG is
\( (1)/(3)\pi \).

User Chris Nelson
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