What number does someone need on the next test to keep the 81 mean if the past 3 tests had 59, 87, 97

Plz ( true - false) all triangles have interior angles whose measure sum to 90.

Can you me find the slope! (30 points)

Th perimeter of a rectangular garden is 150 feet. the length is 50 feet longer than the width, w. which equation could be used to calculate the width of the garden? a.) 2w+ 2(w-50) =150 b.) 2w+50 + 2w =150 c.) 2(w+50) + w =150 d.) 2w+ 2(w + 50) = 150 need asap. will give brainliest !