Distance formula in Cartesian plane

Geometry Level 1

Suppose that point $A=(2, -3)$ is the center of a circle and point $B=(-1, -2)$ lies on the circle. What is the radius of the circle?.

\sqrt{13}

\sqrt{12}

\sqrt{10}

\sqrt{11}

1 solution

Mark Joseph Francisco
Aug 22, 2014

A = (h,k) A = (2,-3) B = (x,y) B = (-1,-2) r² = (x-h)² + (y-k)² r² = (-1-2)² + (-2-(-3))² r² = (-3)² + (1)² r² = 9 + 1 r + √10

A = (h,k) A = (2,-3)

B = (x,y) B = (-1,-2)

r² = (x-h)² + (y-k)²

r² = (-1-2)² + (-2-(-3))²

r² = (-3)² + (1)² r² = 9 + 1

r + √10

Mark Joseph Francisco - 6 years, 9 months ago