Illustration to show that if an angle is bisected, and if a line drawn through the vertex perpendicular to the bisector, this line forms equal angles with the sides of the given angle.

Bisected Angle

Illustration to show that if an angle is bisected, and if a line drawn through the vertex perpendicular…

Illustration to show that the bisectors of two supplementary adjacent angles are perpendicular to each other.

Bisected Angles

Illustration to show that the bisectors of two supplementary adjacent angles are perpendicular to each…

Illustration to show that the bisector of one of two vertical angles bisects the other.

Bisected Angle

Illustration to show that the bisector of one of two vertical angles bisects the other.

Illustration to show that the bisector of two pairs of vertical angles formed by two intersecting lines are perpendicular to each other.

Bisected Angles

Illustration to show that the bisector of two pairs of vertical angles formed by two intersecting lines…

Illustration of a dihedral angle bisected by a plane. "Every point in a plane which bisects a dihedral angle is equidistant from the faces of the angle."

Dihedral Angle With Bisector

Illustration of a dihedral angle bisected by a plane. "Every point in a plane which bisects a dihedral…

Illustration to show that the bisector of the vertical angle of an isosceles triangle bisects the base, and is perpendicular to the base.

Bisected Vertical Angle of an Isosceles Triangle

Illustration to show that the bisector of the vertical angle of an isosceles triangle bisects the base,…

Illustration to show that if through any point in the bisector of an angle a line is drawn parallel to either of the sides of the angle, the triangle thus formed is isosceles.

Angle Bisector Drawn Parallel to A Side

Illustration to show that if through any point in the bisector of an angle a line is drawn parallel…

Illustration used to show "The two perpendiculars to the sides of an angle from any point in its bisector are equal."

Perpendiculars To The Sides Of An Angle

Illustration used to show "The two perpendiculars to the sides of an angle from any point in its bisector…

Illustration used to show "The two perpendiculars to the sides of an angle from any point not in its bisector are unequal."

Perpendiculars To The Sides Of An Angle

Illustration used to show "The two perpendiculars to the sides of an angle from any point not in its…

Illustration showing that the bisector of a given angle is the locus of points equidistant from the sides of the angle.

Angle Bisector

Illustration showing that the bisector of a given angle is the locus of points equidistant from the…

Illustration of the construction used to bisect a given arc.

Construction of Bisecting a Given Arc

Illustration of the construction used to bisect a given arc.

Illustration of the construction used to bisect a given line.

Construction of Bisecting a Given Line

Illustration of the construction used to bisect a given line.

Illustration showing that if two angles of a triangle are equal, the bisectors of these angles are equal.

Angle Bisectors In An Isosceles Triangle

Illustration showing that if two angles of a triangle are equal, the bisectors of these angles are equal.

Illustration used to prove "The line joining the mid-points of two sides of a triangle is parallel to the third side and equal to one half the third side."

Line Joining Midpoints on a Triangle

Illustration used to prove "The line joining the mid-points of two sides of a triangle is parallel to…

Illustration to show that if the diagonals of a quadrilateral bisect each other, the figure is a parallelogram.

Quadrilateral With Diagonals

Illustration to show that if the diagonals of a quadrilateral bisect each other, the figure is a parallelogram.

Illustration to show that if the diagonals of a parallelogram are equal, the figure is a rectangle.

Rectangle With Diagonals

Illustration to show that if the diagonals of a parallelogram are equal, the figure is a rectangle.

Illustrations to show that if two parallel lines are cut by a transversal, the bisectors of the interior angles form a rectangle.

Rectangle Formed When Two Parallel Lines are Cut by a Transversal

Illustrations to show that if two parallel lines are cut by a transversal, the bisectors of the interior…

Illustration used to prove "The line bisecting one side of a triangle and parallel to another side bisects the third side."

Line Bisecting Side of a Triangle

Illustration used to prove "The line bisecting one side of a triangle and parallel to another side bisects…

Illustration used to prove "The bisectors of the angles of a triangle are concurrent in a point which is equidistant from the three sides of the triangle."

Angle Bisectors In A Triangle

Illustration used to prove "The bisectors of the angles of a triangle are concurrent in a point which…

Illustration to show that the bisector of an exterior angle of an isosceles triangle, formed by producing one of the legs through the vertex, is parallel o the base.

Bisector of an Exterior Angle of an Isosceles Triangle

Illustration to show that the bisector of an exterior angle of an isosceles triangle, formed by producing…

Illustration of a triangle showing that when a line parallel to the base of a triangle bisects one side, it bisects the other side also.

Triangle With Bisector Parallel to the Base

Illustration of a triangle showing that when a line parallel to the base of a triangle bisects one side,…

Illustration to show perpendicular bisectors in a triangle. It is known as the circumcenter.

Circumcenter of Triangle

Illustration to show perpendicular bisectors in a triangle. It is known as the circumcenter.

Sketch of equilateral triangle with bisectors, medians, and altitudes.

Equilateral Triangle

Sketch of equilateral triangle with bisectors, medians, and altitudes.

Illustration to show angle bisectors in a triangle. It is known as the incenter.

Incenter of Triangle

Illustration to show angle bisectors in a triangle. It is known as the incenter.

Illustration to show that if one of the legs of an isosceles triangle is produced through the vertex by its own length, the line joining he end of the leg produced to the nearer end of the base is perpendicular to the base.

Leg Produced through the Vertex of an Isosceles Triangle

Illustration to show that if one of the legs of an isosceles triangle is produced through the vertex…

Illustration to show that if the lines joining the middle points of the sides of a triangle divide the triangle into four equal triangles.

Midpoints of Triangle Divide Triangle into Four Equal Triangles

Illustration to show that if the lines joining the middle points of the sides of a triangle divide the…

Illustration used to show the various parts of a triangle: sides, angles, medians, altitudes, bisectors, and segments.

Parts Of A Triangle

Illustration used to show the various parts of a triangle: sides, angles, medians, altitudes, bisectors,…

Illustration to show that the perpendicular bisector of the base of an isosceles triangle passes through the vertex and bisects the angle at the vertex.

Perpendicular Bisector of the Base of an Isosceles Triangle

Illustration to show that the perpendicular bisector of the base of an isosceles triangle passes through…

Illustration used to prove "The perpendicular bisectors of the sides of a triangle are concurrent in a point which is equidistant from the three vertices of the triangle."

Perpendicular Bisectors In A Triangle

Illustration used to prove "The perpendicular bisectors of the sides of a triangle are concurrent in…