Answer: 18.619
Step-by-step explanation:
√ ((X2-X1)2+(Y2-Y1)2)
d = √(7.9-21.7)2+(-2.3-10.2)2
d = √((-13.8)2+(-12.5)2)
d = √(190.44+156.25)
d = √346.69
d=18.619