Answer: 42
Explanation:
a=x1-x2=21-3=18
B=y1-y2=-30-8=-38
These two distances can be considered as the base and vertical side of a right triangle with the distance between the two as the hypotenuse. Then we use the pythagorean theorem to find the hypotenuse, c.
C^2=a^2+b^2
C^2=18^2+-38^2
C^2=1768
C= Square root of 1768=42.0