An arc is 6.5 cm long and it subtends a central angle of \(45^{\circ}\). Find the radius of the circle.

What is the radius of a hemisphere with a volume of \(60,750 cm^3\)

Express the plane \(z=x\) in (a) cylindrical, and (b) spherical coordinates.

Find the length of a diagonal of a \(4 m \times 12 m\) rectangle.