The correct answer is 67 to the third power
3*1+3*2+3*3+,,,+3n= 3*(1+2+...+n)
=3*n(n+1)/2
cause 1+2+...+n=n(n+1)/2
Answer:
114 ft
Step-by-step explanation:
We split the figure into two rectangles. The long triangles perimeter is equal to 30 + 30 + 9 + 9 = 78. Then, the top triangle is equal to 9 + 9 + 9 + 9, which is equal to 36. Then to find the perimeter of the entire figure, we add these two shapes together, 78 + 36, which gets us to our final answer, 114 ft.