The L and the A in theorem stand for leg and

Which math sentence can be used to determine if the triangle is a right triangle?

The weight of full–grown tomatoes at a farm is modeled by a normal distribution with a standard deviation of 18.4 grams. the 95 percent confidence interval for the mean weight of the tomatoes is calculated using a sample of 100 tomatoes. what is the margin of error (half the width of the confidence interval)?

Having a hard time understanding this question (see attachment).