Question

Find the length of the following tangent segments to the circles centered at O and O's whose radii are 5 and 3 respectively and the distance between O and O's is 12. I will post diagram.
1.) The tangent segment AB

Answer 1

$AB^2=12^2-(5-3)^2 \\AB^2=144-4 \\AB^2=140 \\AB=\sqrt{140} \\AB \approx 11.83$