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How many different isosceles triangles have integer side lengths and perimeter 23?

 Dec 21, 2018

Let  x be the equal sides of the  triangle...let y be the remaining side


One way of solving this is with a graph...


We have these constraints  

2x + y = 23

And by the Triangle Inequality, we have

2x > y

x + y > x   ⇒  y > 0


Look at the graph of the feasible region here :  https://www.desmos.com/calculator/kyzw7wa8v5


It shows that there are six such triangles



cool cool cool

 Dec 21, 2018
edited by CPhill  Dec 21, 2018




cool cool cool

CPhill  Dec 21, 2018

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