Question 910899
a^2+b^2=c^2
6^2+8^2=c^2
36+64=c^2
What are we trying to show?
We want to know if the angle formed by the two sides of the triangle is a right angle.
What should c be if it is a right angle? 
If the corner is a right angle, what should the distance be between the two marked points? 
Why can't the answer be c^2=100
What does it mean if c=10?
Why do you think we were using a^2+b^2=c^2
We knew a and  b but  we didn't know c. Now we do.