Question

a certain polygon has 9 sides.Two of the sides have length of a,and 4 sides each have length 3a.The lengths of the remaining three sides are 11,12, and 13.If the perimeter of the polygon is 92,what is the value of a? ​

Answer 1

92 = 11 + 12 + 13 + 2(a) + 4(3a)

92 = 36 + 2a + 12a

92 = 36 + 14a

-36 -36

56 = 14a

56/14 = 14a/14

a = 4