Posted by please help me out!!! please on Monday, February 11, 2013 at 10:53am.
Let O be the center of the circle Γ, and P be a point outside of circle Γ. PA is tangential to Γ at A, and PO intersects Γ at D. If PD=14 and PA=42, what is the radius of Γ.

geometry  Reiny, Monday, February 11, 2013 at 11:27am
In this case the secant  tangent theorem says
PA^2 = PD x PC , where D in on the extension of PO as it hits the circle , making CD a diameter
Let the diameter be 2x , (radius = x)
(14)(2x+14) = 42^2
28x + 196 = 1764
28x = 1568
x = 56
Answer This Question
Related Questions
 Math  Γ 1 is a circle with center O 1 and radius R 1 , Γ 2 is a ...
 math  Let AB be the diameter of circle Γ1. In the interior of Γ1, ...
 Math  Let AB be the diameter of circle Γ1. In the interior of Γ1, ...
 heeeeeelp math  is a point outside of circle Γ. The tangent from P to &#...
 math  Equilateral triangle ABC has a circumcircle Γ with center O and ...
 maths  Equilateral triangle ABC has a circumcircle Γ with center O and ...
 math  Two congruent circles Γ1 and Γ2 each have radius 213, and the ...
 Maths  Given circle Γ and a point P outside of Γ, 2 lines l1 and l2 ...
 circle geometry  Circles Γ1 and Γ2 intersect at 2 distinct points A ...
 geometry  A point P is given outside of a circle Γ. A tangent from P to &#...
More Related Questions