What is the missing side length of the polygon if its perimeter is one hundred forty feet?

An irregular seven sided polygon with sides labeled: eighteen feet, 6 feet, seventeen feet, fifteen feet, forty feet, and twenty-one feet. The seventh side length is unknown.

seventeen feet

twenty feet

twenty-three feet

twenty-nine feet
@matricked @dg2

Question

What is the missing side length of the polygon if its perimeter is one hundred forty feet? 

An irregular seven sided polygon with sides labeled: eighteen feet, 6 feet, seventeen feet, fifteen feet, forty feet, and twenty-one feet. The seventh side length is unknown.

 seventeen feet

 twenty feet

 twenty-three feet

 twenty-nine feet
@matricked @dg2

anonymous · Answer

@hello_j

anonymous · Answer

attachment

anonymous · Answer

Help please!! @dg2 @hello_j  @Hero

anonymous · Answer

Idk it Dx

hero · Answer

Actually, it says the perimeter is 140 ft. The perimeter is the sum of all the sides.

hero · Answer

Add all the sides, then subtract the sum from 140 to find the length of the missing side.