geo
posted by mary .
a graphic artist is using a coordinate plane to design a company logo. the log has an equilateral triangle inscribed in a circle.. The lies in quadrant 1, is tangent to the x and y axis and has a radius of 10 units. one side of the triangle is parallel to the y axis and one vertex is (20,10). Write equation of the circle? What are the lengths of the sides of triangle?

well, we know that with center at (h,k) the circle's equation is
(xh)^2 + (yk)^2 = 100
Since (20,10) is on the circle, at one end of the horizontal diameter, it is clear that the center of the circle is at (10,10).
(x10)^2 + (y10)^2 = 100
Getting the triangle's dimensions should now be no trouble.