. Determine whether a tangent line to circle O is shown in the diagram, for AB = 7.75, OB = 4, and AO = 8.75. Explain your reasoning. (The figure is not drawn to scale.)
If it is a tangent then angle B is a right angle. The easy way to test is with the pythagorean theorem.
7.75^2+4^2=8.75^2
76.0625=76.5625
This means that Angle b is not a right angle so Segment AB is not a tangent (though it is extraordinarily close to being one.)