I have no clue what’s going on help me plz

If you are just building your payment history, how many points from a perfect score will you possibly miss?

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

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?