Remark
You can get an idea of how this should be solved by drawing a diameter from the intersection of the tangent and the circumference of the circle and the center of the circle. When you do this and when you draw an angle from either side of the diarmeter joining the two ends of the diameter to the circumference of the circle you get 90 degrees. See the first diagram on the left.
Now what you want is the chord tangent theorem.
The angle at the intersection of the chord and the the tangent point is one half the size of the arc formed by the endpoints of the chord and the circumference of the circle. See diagram on the right.
step one
Draw a line showing what you are talking about.
Step two
82 * 2 = 164
