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

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

There is a hypothetical state between the USA and Mexico border 'Tango'.
Here 70 percent of the population have defective eyesight, 75 percent are hard of hearing, 80 percent have Nose trouble and 85 percent suffer from allergies, what percentage (at a minimum) suffer from all four ailments?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

what does this below rebus represent identXQQQQQME

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What does this rebus mean?

O
N
C
E
TIME