1. the number a is 4/5 of the number b. what part of number a is number b? 2. the number a is 1/5 smaller than the number b. by how much is b bigger than a?

Writing some equations out might help!

1) You know that a is 4/5 of b. This can be written as:.
To find what b is equal to, multiply both sides by 5/4: .
A is 5/4 B. 

2) You know that a is 1/5 smaller than b. This can be written as: .
To find b, just add 1/5 to both sides: .
B is 1/5 bigger than a. 

Idrk but i think u should figure out the n dia n then the units it will make it way more easier