Question

Suppose someone tells you that she has a triangle with sides having lengths 2.2, 4.5, and 6.7. Is this a right triangle?

Answer 1

You can apply the Pythagorean theorem:
a^2 + b^2 = c^2
c is the longest side of the triangle
2.2^2 + 4.2^2 = 6.7^2
4.84 + 17.64 = 44.89
22.48 =/= 44.89
That is not a right triangle