Question

More 9th grade quadratic equations (this time with circles!)

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Answer 1

Area of a Circle

\[A=πr^2\]


We have two circles

First one has a radius of 6
Second one has a radius of 2x
Area of a shaded region is 220pi

We can represent the area of of the shaded region by subtracting the area of the first circle from the area of the second circle.

\[\pi (2x)^2 - \pi (6)^2 = 220 \pi\]

Answer 2

@Aureo

Answer 3

You can divide by pi and just deal with the two radii and the area of the shaded region.

Answer 4

\[4x^2 - 36 = 220\]

Answer 5

Alright. So then we add 36 to both sides.

Divide by 4

Find the square root of both sides.

And we get 8.

Answer 6

Yeah (:

Answer 7

@Aureo Are you good?

Answer 8

you know what answer now?