What is the height of a right circular cone whose volume is 47.8 inches cubed and whose radius is 3 inches?

Answer 1

The Volume of a right circular cone is denoted by V = 1/3 pi (R^2) H. R = Radius of the circular cross-section of the base. H = Vertical (or perpendicular) height of the cone from the centre of the circular base to it's apex. pi = constant 3.1415926559.................. (the ratio of ANY circle's circumference to it's diameter length). Re-arranging (or transposing) the formula above to make H the subject of the formula gives: H = 3V / [pi (R^2)]. Substituting in the known values for V, and R yields the following result: H = [3 * 47.8] / [3.14 * (3^2)] Therefore, H = [143.4] / [28.27] ---- Therefore, H = 5.07 inches (approx). ANSWER. Note: To maintain accuracy during the calculations, it is best to leave pi within the calculator display as it is (i.e. to several decimal places). Only round up/down to 2 d.p. at the END of the process. If this is done too early, the finla answer may be quite a bit out! Since all criteria given was to 2 d.p. or less, I presumed the level of accuracy required for the answer would be the same! STEVE EASTOP.