The perimeter of a geometric figure is the sum of all of the sides.
Here, we want the perimeter of a triangle. A triangle has 3 sides and its perimeter will be the sum of these 3 sides.
Given,
Side 1 = 30 feet
Side 2 = 40 feet
Side 3 = 50 feet
We can easily find the perimeter of the triangle by summing the three lengths.
Perimter = 30 + 40 + 50 = 120 feet
Answer
120 feet