Question

Find the length of the radius of the given circle.

(x - 5)2 + (y + 3)2 = 25

Answer 1

you have (x−h) 2 +(y−k) 2 =r 2 the equation for a circle with radius r
since r 2 =25 you know r=5

Answer 2

thank you

Answer 3

your welcome

Answer 4

All you need to do is complete two squares.

x2 + y2 - 4x - 6y - 12 = 0

x2 - 4x + y2 - 6y = 12

x2 - 4x + 4 + y2 - 6y + 9 = 12 + 4 + 9

(x - 2)2 + (y - 3)2 = 25 = 52

Thus it has the center at (2,3) and a radius r = 5.