There are 3 black marbles in and 4 red marbles in a bag. what is the probability that you will pick two black marbles put of the bag without replacing the first one?

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?

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?

Tom drove 206 miles in 3.9 hours. estimate his average speed.