I am assuming 10 and 12 are the legs and 23 is the hypotenuse?
With that said, we can use the pythagorean theorem a^2+b^2=c^2
a^2+b^2=c^2 = Right triangle
a^2+b^2 < c^2 = abtuse
a^2+b^2 > c^2 = acute
10^2 + 12^2 = 23^2
244 = 529
244 < 529
It is abtuse
