Let XY be a tangent to a circle, and let be a XBA secant of the circle, as shown below. If AX = 16 and XY = 10, then what is AB?
Tangent - Secant Theorem that says that
XB ( XB + BA) = XY^2
XB ( AX) = XY^2
So
XB ( 16) = 10^2
XB (16) = 100
XB = 100 / 16 = 6.25
AB = AX - XB
AB = 16 - 6.25
AB = 9.75
