Geometry Glossary - B

 

Base (of an isosceles triangle):

the side opposite the vertex angle

 

Base angles (of an isosceles triangle):

the two angles that share the base as a common side

Base (of a surface):

the face, or congruent faces, which determine the name of the surface

Betweenness:

a point Q is between A and B if and only if Q, A, and B are collinear, and if AQ + QB = AB

Bisector of an angle:

a ray or segment anchored at the vertex, which divides the original angle into two congruent angles

Bisector of a segment:

a point, line, or segment that divides a segment in half