Question

10 POINTS!! Made myself broke with my last two questions!

The center of circle O is the origin. Circle O passes through the point (−5, −12). What is the length of the radius of circle O?
A. √ 17
B. 7
C. √ 119
D. 13

Answer 1

D

Explanation:

The radius r is the distance from the centre to a point on the circle.

Calculate r using the distance formula

r = √ (x₂ - x₁ )² + (y₂ - y₁ )²

with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (- 5, - 12)

r =
`√((-5-0)^2+(-12-0)^2)`

=
`√((-5)^2+(-12)^2)`

=
`√(25+144)`

=
`√(169)`

= 13 → D