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

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

What can jump higher than a building?

What 5-letter word typed in all capital letters can be read the same upside down?

A man is approaching a broad and barren land. He has a package with him. If somehow, he is unable to open the package before reaching the land, he will die.

Can you guess what is present in the package?

The answer I give is yes, but what I mean is no. What was the question?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

A person is found murdered in his Chamber. When the crime scene is investigated, the Investigator find out that there is a calendar on which the victim has written a few numbers with his blood. The numbers are 4, 11, 11 and 4.

There are four suspects in the murder, John, Jacob, Anna and Lee. Can you find out who is the murderer?

Find the next number in the series below

21 32 54 87 131 ?