SOLUTION: An aluminum plate is made according to the following dimensions. The outer radius is 10 inches and the inner radius is 3 inches. Use p = 3.14 as an approximate value. (a) How man

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Question 154877: An aluminum plate is made according to the following dimensions. The outer radius is 10 inches and the inner radius is 3 inches.
Use p = 3.14 as an approximate value. (a) How many square inches in area is the aluminum plate? (b) If the cost to construct the plate is $7.50 per square inch, what is the construction cost?
Can you please explain this to me with an algebraic example? Thank you.
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
a) get the Area of the Outer Radius=R + Inner radius=r
Remember: A=pi%28R%5E2%29%2Bpi%28r%5E2%29=pi%28R%5E2%2Br%5E2%29
So, A=pi%2810%5E2%2B3%5E2%29=pi%28100%2B9%29
A=109pi%28in%5E2%29=342.4336in%5E2
b)Rate=Price%2Farea*Area
%287.50%2Fcross%28in%5E2%29%29%2A%28342.4336cross%28in%5E2%29%29
$2568.252 ---------------------> cost to make it
Thank you,
Jojo