Geometry 90 points ! find lateral and surface area

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

The length of a rectangle is x times the square root of 100. the width is one-half y more than three-halves x. given that the area of the rectangle is 125 cm2, which equation could represent the rectangle in terms of x and y? a) 5xy − 15x = 125 b) 5xy + 15x = 125 c) 15x2 − 5xy = 125 d) 15x2 + 5xy = 125

An elevator travels 310 feet in 10 seconds. at that speed, how far can't his elevator travel in 12 seconds?