# Thread: Write an equation and solve

1. ## Write an equation and solve

Set up with an equation and solve:Suppose the perimeter of a triangular lot is 100 m. If the length of the shortest side is 10 m less than the middle-length side and the length of the longest side is 25 m more than the shortest side, determine the length (in m) of the middle-length side.

must be in an improper fraction. It's giving me a head ache.

2. Hello.

which parts giving you a headache?

Just draw a triangle and list the variables.

So:
Let M = the Middle length side side

Shortest side = M - 10
Middle length side = M
Longest side = M - 10 + 25 = M + 15

And we know perimeter is 100m.

That would mean Shortest side + Middle length side + Longest side = 100m

I think you should be able to solve it from there. =)

3. well this is the equation i ended up with

x + x -10 + x + 25 = 100
3x + 15 = 100
x = 85/3 (needs to be improper)

4. Originally Posted by Anthp08
Set up with an equation and solve:Suppose the perimeter of a triangular lot is 100 m. If the length of the shortest side is 10 m less than the middle-length side and the length of the longest side is 25 m more than the shortest side, determine the length (in m) of the middle-length side.

must be in an improper fraction. It's giving me a head ache.
Let M= middle side length

then shortest side = M-10

longest side = M - 10 + 25 = M + 15

Perimeter = 100

M + M - 10 + M + 15 = 100

3M = 95

$\displaystyle M = \frac {95}{3}$

$\displaystyle = 31\frac{2}{3}$

middle side $\displaystyle = \frac {95}{3}\;metres = 31\frac{2}{3}$ metres.

5. thank you, i knew it was something small like that, was driving me crazy why i missed it though.