Part A. 20
Part B. 24
To do this, use the Pythagorean Theorem
a^2+b^2=c^2
C will always represent the hypotenuse. While a and b will represent the other legs.
1. 16^2+12^2=c^2
256+144=c^2
400=c^2
Square root both sides
20=c
2. 10^2+b^2=26^2
100+b^2=676
Subtract 100 from both sides
b^2=576
Square root both sides
b=24