Question 934466
The length EA can be found with Distance Formula.  This will be the length of the radius.  k can then be found because EA=EB.


{{{EA=sqrt((2-(-2))^2+(3-0)^2)}}}
{{{sqrt((4)^2+(3)^2)}}}
{{{sqrt((16)^2+(9)^2)}}}
{{{sqrt(25)}}}
{{{highlight_green(5=r)}}}


Knowing E(2,3) is the center, according to standard form equation of a circle,
The equation for this circle is {{{highlight((x-2)^2+(y-3)^2=25)}}}.


Part (b) is more work to solve.
Find slope of EA.
Form the negative reciprocal of that slope.
The line tangent at point A and perpendicular to the segment EA can be found  (its equation).
Using this new equation, determine its y-intercept.
I have not worked through this part completely.  Your triangle might or might not be a Right triangle.