Answer:
Step-by-step explanation:
Radius = diameter ÷ 2
Diameter = distance between C and D
Find the distance using distance formula
[tex]Diameter, CD = \sqrt{(-7-1)^2 + (-4-2)^2} = \sqrt{8^2 + 6^2} = \sqrt{100} = 10 \ units\\\\Therefore , radius = \frac{Diameter }{2} = 5 \ units[/tex]