How do I prove this?

The vertices of a triangle are a(7,5), b(4,2), c(9,2). what is m

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%

What is the scale factor of two similar pyramids with volumes of 64 cubic feet and 8 cubic feet