Answer:
Know precise definition of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.
term definition
Perpendicular line segments - two line segments which cross to form 90 degree angles
right angle - a 90 degree angle
equilateral triangle - a triangle with all sides equal and all angles equal
scalene triangle - a triangle having three unequal sides and angles
