Question 840910
An EQUILATERAL triangle has 3 sides with the same length.
If one side is 40 feet long, the other two sides are 40 feet long too.
The sum of the length of all 3 sides (called the perimeter) of that triangle is
{{{40 feet+40 feet+40 feet=highlight(120 feet)}}} .
That is the distance Amy walked around the flower bed.
 
You are confusing problems.
This problem is about an equilateral triangle, with a side measuring 40 feet.
You were thinking of an isosceles triangle, with an angle measuring {{{40^o}}} .
An ISOSCELES triangle has two sides of equal length, opposite angles of equal measure. In an isosceles triangle with one smaller angle measuring {{{40^o}}} ,
the other two angles would add up to {{{140^o}}} , measuring {{{70^o}}} each.
You knew that because you know that the measures of the angles of a triangle add up to {{{180^o}}} .