Help I don’t know this

Question

An isosceles trapezoid has a perimeter of 35kilometers. Its shorter base measures 12kilometers and its longer base measures 15kilometers. The two remaining sides have the same length; what is that length?

Answer 1

Your isosceles trapezoid is a quadrilateral (i.e., 4 sides/4 angles). The sum of the lengths of its 4 sides is 35 km. Do the following subtraction: 35 - 12 -15 = 8; 8 is the sum of the lengths of the remaining 2 (equal length) sides. Divide 8 by 2 and you have the length of each of the remaining 2 sides---4 km.