Answer:
Step-by-step explanation:
1. 10^2+7^2=x^2
x=sqrt(149)
2. 21^2-19^2=x^2
x=sqrt(80)
3. This is all pythagorean theorem busywork, a^2+b^2=c^2 where c is the hypotenuse of the triangle. I think from my examples you should be able to figure the rest out.
