Provide a rule to describe the relationship between the number in the sequence

1,4,9,16​

Find the distance between (7,-6) and (-3,-9)

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?

Need so much on this one how many yards?