If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

I can be cracked, made, told, and played. What am I?

In the Chess Board picture below white army is arranged. You need to add a black army on the board such that no piece is under any threat.
Note: Army comprised of 1 king, 1 queen, 2 rooks, 2 bishops, 2 knights, and 8 pawns.

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

What does this rebus picture identify?

What does man love more than life, hate more than death or mortal strife; That which contented men desire; the poor have, the rich require; the miser spends, the spendthrift saves, and all men carry to their graves?

Find the missing number in the sequence below:

What four weights can be used to balance from 1 to 30 pounds?

Solve the puzzle by telling what does below picture means.