If the side lengths of a triangle are 3, 6, and 7, then the triangle is obtuse. true or false?

To test this, we first sum the squares of the 2 shortest sides:
sum = 3^3 + 6^2 = 9 + 36 = 45

7^2 = 49

If the sum is less than the square of the third side (as is the case here) then the triangle is obtuse.

Source:
http://www.1728.org/triantest.htm