Consider the following pairs:

A frustum of a cone has a lower base radius of 5 cm, an upper base radius of 3 cm, and a height of 4 cm. What is the volume of the frustum?

A pipe can fill a tank in 6 hours, while another pipe can empty it in 8 hours. If both pipes are opened together, how long will it take to fill the tank?

If z=2+3i, then arg(z)=θ lies in which quadrant?

'Symbian' is a_______

The diagonals of a rhombus are 16 cm and 12 cm. Find the area of the rhombus.

How many sides does a regular polygon with each interior angle measuring 140° have?

In a triangle, the inradius is 6 cm, the circumradius is 9 cm, and the area is 54 cm². What is the semiperimeter of the triangle?