A movie is projected onto a screen that is 20 feet tall and touches the ground. If the projector sits on the ground and is 40 feet from
the base of the screen, the angle of projection, with relation to the ground, is
degrees. (Round to the nearest tenth.)

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%

Which one is the correct answer, and why?

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ac=26 and ch=8, find bh.