SOLUTION: I am having a real hard time with this word problem. Thanks. A semicircular window of radius 15 inches is to be laminated with a sunblock coating that costs $0.85 per square in

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Question 73616: I am having a real hard time with this word problem. Thanks.
A semicircular window of radius 15 inches is to be laminated with a sunblock coating that costs $0.85 per square inch to apply. What is the total cost of coating the window, to the nearest cent? (Use p = 3.14. Hint: Area of Circle: A = prē)

Answer by joyofmath(189) About Me  (Show Source):
You can put this solution on YOUR website!
The area of the semicircular window is half of what the area would be if the window were a whole circle. The area is thus %281%2F2%29%2Ap%2Ar%5E2 = %281%2F2%29%2Ap%2A15%5E2 = %281%2F2%29%2Ap%2A225. Replace p with 3.14 and the area of the semicircle = %28225%2F2%29%2A3.14 = 112.5%2A3.14 = 353.25 square inches. The cost per square inch = $0.85 so the total cost = 353.25%2A.85 = $highlight%28300.26%29.