Answer:
43 cm
Step-by-step explanation:
If the longest side of the triangle is 8 cm longer than five times the shortest side
5s + 8
the third side is 7 cm less than four times the shortest side
4s - 7
The perimeter of a triangle is 71 cm
s + (4s - 7) + (5s + 8) = 71
Combine like terms
10s + 1 = 71
Subtract 1 from both sides
10s = 70
divide both sides by 10
s = 7
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How long is the longest side of the triangle
5s + 8
5(7) + 8
35 + 8
43
