2/c = 4/9

(these are fractions btw)

The center of a circle represent by the equation (x+9)^2+(y-6)^2=10^2 (-9,6), (-6,9), (6,-9) ,(9,-6)

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.