5/13
The x value is negative (second quadrant). 13 is the hypotenuse. So the missing side is 13^2 = (-12)^2 + y^2.
Sin theta is the opposite (5) over hypotenuse (13).
The midpoint of a line can be represented by the point that is in the very center of the line. A line segment such as AT also represents half of the line. The symbol of the tilde with the equal sign underneath represents congruence meaning the two segments are the same. Therefore each equation shows the same true statement in a different form
the circumference is 20pie or 62.83185307
