SOLUTION: One side of a triangle is one-third the longest side. The third side is 13 feet less than the longest side. The perimeter is 85. Find all three sides.

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Question 1124892: One side of a triangle is one-third the longest side. The third side is 13 feet less than the longest side. The perimeter is 85. Find all three sides.
Found 3 solutions by solver91311, MathLover1, MathTherapy:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Let represent "One side". Then the longest side is and the third side is .

The perimeter of a triangle is given by the sum of the measures of the three sides, hence:



Solve for then calculate and


John

My calculator said it, I believe it, that settles it


Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let's sides be a,b, and c where c is longest
if one side of a triangle is one-third the longest side, we have
a=c%2F3....eq.1

if the third side is 13 feet less than the longest side, we have
b=c-13.......eq.2

if the perimeter is 85, we have
a%2Bb%2Bc=85....eq.3 .............substitute a and b

c%2F3%2Bc-13%2Bc=85...solve for c
c%2B3c-13%2A3%2B3c=85%2A3
7c-39=255
7c=255%2B39
7c=294
c=294%2F7
c=42
now find a and b

a=c%2F3->a=42%2F3->a=14
b=c-13->b=42-13->b=29

so, your sides are: highlight%28a=14%29,highlight%28b=29%29, and highlight%28c=42%29

check the perimeter:
a%2Bb%2Bc=85
14%2B29%2B42=85
85=85


Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

One side of a triangle is one-third the longest side. The third side is 13 feet less than the longest side. The perimeter is 85. Find all three sides.
Just ONE (1) variable is needed to solve for the value of all 3 sides
Let the first side be F
Then the longest side is 3F
Third side = 3F - 13
We then get: F + 3F + 3F - 13 = 85
7F - 13 = 85
7F = 98
F, or first side = highlight_green%28matrix%281%2C4%2C+98%2F7%2C+%22=%22%2C+14%2C+feet%29%29
Longest side: highlight_green%28matrix%281%2C4%2C+3%2814%29%2C+%22=%22%2C+42%2C+feet%29%29
Third side: highlight_green%28matrix%281%2C4%2C+3%2814%29+-+13%2C+%22=%22%2C+29%2C+feet%29%29