SOLUTION: I need to know the sq. ft of surface area in a 2" x 4" oval pipe. The pipe is 6'4" long. This a running board on a truck that I am painting. I have two of them.. Again, I nee

Algebra ->  Surface-area -> SOLUTION: I need to know the sq. ft of surface area in a 2" x 4" oval pipe. The pipe is 6'4" long. This a running board on a truck that I am painting. I have two of them.. Again, I nee      Log On


   

Question 1097210: I need to know the sq. ft of surface area in a 2" x 4" oval pipe. The pipe is 6'4" long.
This a running board on a truck that I am painting. I have two of them..
Again, I need to know the total surface area
Thank You
William Brown
My email is:
1RAM5689@gmail.com
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
If the pipe can be approximated by an ellipse, then you can use Area = perimeter*length. Since the major radius is less than 3 times the minor radius, the perimeter, P, of the pipe USING the ELLIPSE APPROXIMATION is:
P = ++2%2Api%2Asqrt%28%28%28a%5E2+%2B+b%5E2%29%29%2F2%29+
where a and b are the major axis and minor axis lengths, respectively (similar to radius of a circle, except for a circle a=b=r).
We have
a=4/2 = 2 in.
b = 2/2 = 1 in.
P = ++2%2Api%2Asqrt%28%282%5E2+%2B+1%5E2%29%2F2%29+ or approx. 9.9346 in.
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Length of running board is 6*12 + 4 = 76 in.
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Surface area = P * length = 9.9346 in. * 76 in = 755.03 sq in.
Since you have two of them, that brings the total area to 2*755.03 = 1510.06 sq in. or, converting to sq ft: 1510.06/144 = 10.49 sq ft.