Question

Is a triangle with sides of length 6ft, 21 ft, 23 ft a right triangle

Answer 1

According to the pythagorean theorem a^2+b^2=c^2 where c is the largest side. The square root of 6^2+21^2=21.84 which does not equal 23. So it is not a right angle triangle.

Answer 2

Try the Pythagorean theorem, $a^{2} + b^{2}= c^{2}$. Does $6^{2} + 21^{2} = 23^{2}$? If it does, you have yourself a right triangle. If it doesn't, then it isn't a right triangle.