I think the answer is 16x^2+1
<u>Part 1)</u> A 20° sector in a circle has an area of 21.5π yd².
What is the area of the circle?
we know that
the area of a circle represent a sector of
degrees
so by proportion
therefore
<u>the answer part 1) is</u>
The area of the circle is 
<u>Part 2)</u> What is the area of a sector with a central angle of 3π/5 radians and a diameter of 21.2 cm?
we know that
the area of the circle is equal to

where
r is the radius of the circle
in this problem we have

<u>Find the area of the circle</u>



<u>Find the area of the sector</u>
we know that the area of the circle represent a sector of
radians
by proportion
therefore
<u>the answer part 2) is</u>
the area of the sector is

1/4 is the same thing as 25%. So we know that we have to find 25% of 2000 pounds, which is 1 ton. Convert 25% into a decimal and then multiply.
2000 times .25 is 500.
One fourth of one ton is 500 pounds.
What the formula?
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