How many non-congruent triangles with perimeter 15 inches are there whose side lengths are all integer numbers of inches?

mathisopandcool May 12, 2021

#1

#2**0 **

thxs:) is there any other way to solve it other than just finding all the possible combinations?

mathisopandcool
May 12, 2021

#3**0 **

Absolutely, but I think this way might just be the best way for small cases like this.

It is actually quite efficient if you have a system.

15/3 = 5

15/2 = 7.5

So the highest number has to be 5-7.

5: 1 option

6: 2 options

7: 4 options

You could also use complementary counting, find all numbers that add up to 15, then subtract the ones that don't work for a triangle. :))

=^._.^=

catmg
May 12, 2021