Find the length of the missing side of a triangle if one side is 14 inches and the other is 7 inches

The perimeter of a stage is 116 feet. it is 17 feet wide. how long is it?

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)