1. 所有的角

alternate angle内错角?

corresponding angle同位角?

vertical angle对顶角?

central angle 圆心角?

interior angle内角?

exterior angle外角?

supplementary angles补角?

complementary angle余角?

adjacent angle邻角?

acute angle锐角?

obtuse angle钝角?

right angle直角

round angle周角?

straight angle平角?

included angle夹角??

2. 所有的三角形

equilateral triangle等边三角形?

scalene triangle不等边三角形?

isosceles triangle等腰三角形?

right triangle直角三角形?

oblique斜三角形?

inscribed triangle内接三角形?

3. 有关收敛的平面图形，除三角形外?

semicircle半圆?

concentric circles同心圆?

quadrilateral四边形?

pentagon五边形?

hexagon六边形?

heptagon 七边形?

octagon八边形?

nonagon九边形?

decagon十边形?

polygon多边形?

parallelogram平行四边形?

equilateral等边形?

plane平面?

square正方形，平方?

rectangle长方形?

regular polygon正多边形?

rhombus菱形?

trapezoid梯形?

4. 其它平面图形

arc弧?

line, straight line直线?

line segment线段?

parallel lines平行线?

segment of a circle弧形