In science class, the ratio of boys to girls is 2:3. If there are 21 girls in the class, how many boys are there?

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

Look at triangle wxy what is the length (in centimeters) of the side wy of the triangle?

Find the length of the radius of a circle with the center at -7+2i and a point in the circle at 33+11i