Which equation can be simplified to find the inverse of

The area of square garden is 300m squared. how long is the diagonal?

An engineer scale model shows a building that is 3 inches tall. if the scale is 1 inch = 600 feet, how tall is the actual building?

Angie has saved 3/8 of the amount she needs to buy a bike. clive has saved 7/10 of the amount he needs to buy a skateboard. what is the difference between clive's and angie's fraction of savings?