## EXERCISES 11.1

**Explain the formula in the text for angle measure in the Cartesian model.**
- Find the perpendicular line from (2, 3) to t = {(x, A 1 2x + 3v = 5).
- Find a coordinate function for f = {(x, A I 2x + 3y = 51.

11.2 THE POINCARE DISK MODEL FOR HYPERBOLIC GEOMETRY