APPENDIXC Glossary
absolute value The distance of a number from zero, without regard to direction.
acute angle An angle that measures less than 90s.
acute triangle A triangle that has three acute angles.
addend The numbers that are added when addition is performed.
adjacent angles A pair of angles that have the same vertex and share a side, but do not overlap
one another.
algorithm A list of steps necessary to perform a process.
alternate interior angles Two angles that are on opposite sides of a transversal and between
the parallel lines.
altitude A line segment from a vertex of a triangle perpendicular to the opposite side.
angle Two rays with a common endpoint.
angle bisector A line, ray, or segment that passes through the vertex of an angle and cuts it
into two angles of equal size.
angle bisector in a triangle A line segment from the vertex of an angle to the opposite side of
the triangle that divides the angle into two congruent angles.
apothem A line segment from the center of a polygon perpendicular to a side.
arc A portion of a circle.