# Thread: equation of a circle given the tangents

1. ## equation of a circle given the tangents

Can someone please explain the steps to solve this problem? I'm taking the ACT on Thursday and am trying to teach myself Trig.

A circle in the std. (x,y) coordinate plane is tangent to the x-axis at 5 and tangent to the y-axis at 5. What is the equation of the circle?

2. Originally Posted by ninobrn99
Can someone please explain the steps to solve this problem? I'm taking the ACT on Thursday and am trying to teach myself Trig.

A circle in the std. (x,y) coordinate plane is tangent to the x-axis at 5 and tangent to the y-axis at 5. What is the equation of the circle?
standard equation for a circle ...

$(x - h)^2 + (y - k)^2 = r^2$

center is at coordinates $(h,k)$ and has radius $r$

center is at the point $(5,5)$ , with radius $5$
$(x-5)^2 + (y-5)^2 = 5^2$