The height of a right cylinder is 2.5 times its radius. If the surface area of the cylinder is \(448 \pi\), what is the radius of the cylinder in centimeters?
Area of cylinder: \(2\pi r^2+2\pi rh\)
\(2\pi \:\:r^2+2\pi \:\:r\left(2.5r\right)\)
\(7\pi \:r^2=448\pi \)
But a radius can't be negative so our radius is \(8\)!!!