A marble is selected at random from a jar containing 10 red marbles, 60 yellow marbles, and 30 green marbles. Find the theoretical
probability that it is either red or green

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?

8.74 rounded to the nearest whole number

The base of a rectangular pyramid is 13 inches long and 12 inches wide. the height of the pyramid is 8 inches. what is the volume of the pyramid