Answer: All of them can be a triangle except for #11 because the two shortest sides don't add up to more than the longest side.
#10 is a Pythagorean Triple so it is a right triangle.
To determine if the triangle is an acute or obtuse triangle, we just need to plug the values into the Pythagorean Theorem. If the sum of the legs squared is greater than the hypotenuse, it's an acute triangle. If the sum of the legs square is less than the hypotenuse, it's an obtuse triangle.
Using this logic, 7 & 12 will be obtuse while 8 & 9 will be acute.
