Asquare has an area of 36cm2. what is the perimeter

If 20% of a number is 35, what is 50% of that number?

How do i do this? i don’t understand

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236