Question

Can the lengths 15 cm, 12 cm, 9 cm, form a triangle?

Answer 1

Yup

Explanation:

A right triangle defines as two of the lower sides squared being equal to the longest side squared. This might come as little complex but to provide an example...

3,4,5 triangle.
`3^2=9`
`4^2=16`
`5^2=25`
`9+16=25` (Remember, the lowest sides "3 and 4" squared are being added and it equals the longest side squared or 5 squared.)
Therefore 3,4,5 triangles exist.

It's similar to this situation because...
`9^2=81`
`12^2=144`
`15^2=225`
`81+144=225`
Therefore yes, it is a right triangle.