The base of a triangle is 3,4,√(38) meter feet. Prove that its greatest angle is greater than 120°

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

Aladder that is 20ft long is leaning against the side of a building. if the angle formed between the ladder and the ground is 75 degrees how far is the bottom of the from the base of the building?

Varies inversely with x. if y=8.5 when x=-1 find x when y=-1