Problema Solution
the formula for the surface area of a cylider is: A= 2pirh + 2pir^2
If the height of the cylinder is 10 inches, and the surafce area is 200 sq. inches, determine the length of the radius.
Answer provided by our tutors
Q. height of the cylinder as given in the question is h = 10 inches
let the radius of the cylinder is r inches,
hence,
2pi*r(r+h) = 200
=> r(r+h) = 200/2pi
=> r(10+r) = 31.83
=> r^2 + 10r - 31.83 = 0
by quadratic formula, we have r = 2.538 or -12.53
since length of radius cant be negative therefore,
radius of the cylinder is 2.538 inches