Question

A circle whose center is at (1, -3) passes through (7, 5).

What is the length of the radius of the circle?

Answer 1

10 units

Explanation:

Length of the radius of the circle will be equal to the distance between the center of the circle and the point through which it passes.

Therefore,

Length of radius

`= \sqrt{(1 - 7)^(2) + {( - 3 - 5)}^(2) } \\ \\ \sqrt{ {( - 6)}^(2) + ( - 8)^(2) } \\ \\ = √(36 + 64) \\ \\ = √(100) \\ \\ = 10 \: units`