Question 1066747
A = pi*r^2 + 2pi*r*h = surface area of steel cylinder
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Find the required radius of A = 125,000mm^2 and h= 150mm.
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That's the lateral area and one end.
A = pi*r^2 + 2pi*r*h = 125000
pi*r^2 + 2pi*r*150 = 125000
r^2 + 300r - 125000/pi = 0
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*[invoke solve_quadratic_equation 1,300,-125000/pi]
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r =~ 99.577 mm
Ignore the negative solution.