Answer:
first side = 17 ft
second side = 28 ft
third side = 26 ft
Step-by-step explanation:
a + b + c = 71
b = a + 11
c = 2a - 8
a = first side lenght
b = second side lenght
c = third side lenght
a + (a+11) + (2a-8) = 71
4a + 11 - 8 = 71
4a + 3 = 71
4a = 71 - 3
4a = 68
a = 68/4
a = 17
b = a + 11
b = 17 + 11
b = 28
c = 2a - 8
c = 2*17 - 8
c = 34 - 8
c = 26
Check:
17 + 28 + 26 = 71