| Definition | PG Term |
| Two angles whose sides form two pairs of opposite rays. The angles form an 'X'. | |
| A triangle with three congruent sides | |
| y-y1=m(x-x1) | |
| The point where three altitudes intersect in a triangle | |
| Two angles that are formed by parallel lines and a transversal and lie between the parallel lines and on opposite sides of the transversal. | |
| A segment that connects the midpoints of a triangle or trapezoid. | |
| Two angles formed by two parallel lines and a transversal that lie on the interior of the parallel lines and on the same side of the transversal. | |
| Two angles that are formed by parallel lines and a transversal and lie outside the two lines and on opposite sides of the transversal. | |
| A triangle with no congruent sides. | |
| The 'then' part of a conditional statement. | |
| a dot. | |
| a segment drawn from a vertex perpendicular to the opposite side | |
| The side of a right triangle that is opposite the right angle. | |
| Points that lie on the same line. | |
| An angle whose measure is equal to 90 degrees | |
| (y2-y1)/(x2-x1) | |
| Two lines that intersect to form a right angle. | |
| Points that lie in the same plane. | |
| A line drawn perpendicular to a side through its midpoint. | |
| The point where three perpendicular bisectors intersect in a triangle. | |
| SSS | |
| a ray that divides an angle into two angles that are congruent. | |
| The side opposite the right angle in a right triangle | |
| HL | |
| Two polygons such that their corresponding angles are congruent and the lengths of corresponding sides are proportional | |
| A triangle with three congruent angles. | |
| The point where three angle bisectors intersect in a triangle | |