Number 21 determine if line ab is tangent to the circle. justify your answer. correct answer will get brainliest.

In order for segment AB to be tangent to the circle, angle CAB would have to be  90 degree angle. To determine this, we use the Pythagorean theorem (a^2+b^2=c^2). If it is true, then it is a right angle.

12^2+4^2=13^2
144+14=169
160<169
The Pythagorean theorem in this case does not work, so angle CAB is not a right angle; therefore segment AB is NOT tangent to the circle.