Can you please help me and my grandson? It says:

The length of the sides of the triangle are 5m, 6m, and 7m. Is the triangle acute, right, obtuse?

How can I check my answer to see if it was right?

it's a right triangle if the longest side qualifies as an hypotenuse: a^2+b^2=c^2

Since 7^2 < 5^2+6^2

the triangle is acute.

Similarly, if the c^2 > a^2+b^2, the triangle is obtuse.