Max has sticks of lengths 6, 7, 8, and 10 inches. he wants to make a right triangle for an art project. which 3 sticks should he use?

So this is where the Pythagorean theorem comes in: a squared + b squared = c squared. 

One of the basic pythagorean triangles is the 3-4-5 triangle and you can use any multiples of that triangle and get a right triangle (like multiple 3-4-5 by 2 to get a 6-8-10 right triangle, multiple 3-4-5 by 3 to get a 9-12-15 triangle, etc). 

So you could do 6, 8, and 10. 6 squared is 36, 8 squared is 64, and 10 squared is 100. 36 + 64 = 100, so it works.