For Exercises 8 and 9, refer to the second tiling in the bottom row of Figure 20.4 on page 831, which shows a tiling by isosceles triangles.
9. Every vertex except the center vertex has the same vertex type, in terms of the measures of the angles surrounding the vertex. What is that vertex type?
9.
At each of the vertices except the center one, six triangles meet, with angles (in clockwise order) of 75°, 75°, 30°, 30°, 75°, and 75°.