Question

HELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP

A cone with height h and radius r has volume V = 13πr2h. If a certain cone with a height of 9 inches has volume V = 3πx2 + 42πx + 147π, what is the cone’s radius r in terms of x?

Answer 1

V = 13πr2h

3πx2 + 42πx + 147π = 13πr2(9)

3πx2 + 42πx + 147π = 117πr2

r2 = (3πx2 + 42πx + 147π) / 117π

r = √((3πx2 + 42πx + 147π) / 117π)