Question

Please help me! AB is tangent to circle O at B. Find the length of the radius r for AB=8 and AO=11.7.

Answer 1

AB^2=BO^2-AO^2
=(BC+CO)^2-AO^2
=(11.7+8)^2-(8)^2
(19)^2-(8)^2
(19+8)(19-8)
(27)(11)
sqrt(27*11)=sqrt(27)*sqrt(11)=5.1*3.3= =16.8

i did this but my answer doesnt fit any of my choices

Answer 2

10

It's a right triangle, a^2+36=136.89
so 10.04