What is the length of the line segment marked d in the rectangular prism?

Naomi’s parents want to have 50,000, saved for her college education, if they invest 20000 today and earn 7% interest compound annually, about how long will it take them to save 50 thousand

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

My math teacher told my class to "steal" a 6th grade fraction word problem from the internet, word problems? : -p requirements: only a 1 step word problem. needs to be complex.