radians, 66
ratios, 8-9
simplifying, 10
using to solve problems, 11-12
ray, 51
reciprocal, 15-16
recursion, 145
relative position, 269
rendering loop, 242
resource manager, 253
creating, 253-254
resources, 253
creating surfaces from, 254-255
managing, 253-254
return keyword, 139
right angle, 51, 52
right triangles, 54, 58-59
root element, 253
creating, 251-252
root node, 206
rotation, 248
setting for surfaces, 248
run-time errors, 85-86