Octagon = 8-side polygon
Find area of 1 triangle:
Area of one side triangle = 60 ÷ 8 = 7.5 m²
Given area and length, find height:
Area of each triangle = 7.6 m²
Length of each triangle = 3m
Area = 1/2 x base x height
7.5 = 1/2 x 3 x height
Heigth = 5m
Answer: Slanted Height = 5 m