Answer:
see explanation
Step-by-step explanation:
the perimeter is the sum of the 3 sides of the triangle
add the parts of the ratio 21 + 8 + 14 = 43
divide the perimeter by 43 to find the value of one part of the ratio
= 5 ft ← 1 part of the ratio, hence
21 parts = 21 × 5 = 105 ft
8 parts = 8 × 5 = 40 ft
14 parts = 14 × 5 = 70 ft
the 3 sides of the triangle are 105 ft, 40 ft and 70 ft