My Geometry Dictionary

By: Kelly Park

Acute Triangle

An acute triangle is a triangle with 3 acute angles.


Congruent means to have the same size and shape.


A decagon is a polygon with 10 sides and 10 angles.

Equilateral triangle

A equilateral triangle is a triangle with 3 congruent sides.


A heptagon is a polygon with seven sides and seven angles.


A hexagon is a polygon with 6 sides and 6 angles.

Isosceles Triangle

A isosceles triangle is a triangle with 2 congruent sides.


A nonogon is a polygon with 9 sides and 9 angles.

Obtuse triangle

A obtuse triangle is a triangle with one obtuse angle.


An octogon is a polygon with 8 sides and 8 angles.


A parallelogram is a polygon in which opposite sides are parallel and are congruent.

Plane Figure

A plane figure is a 2-D figure. ( flat )


A polygon is any shape that is closed and has 3 or more sides, no curved lines, and no lines can be crossing over each other.


A quadrilateral is a plane figure with 4 sides. (Quad means 4)


A rectangle is a quadrilateral with 4 sides and 4 right angles.

Regular Polygon

A regualr polygon is a polygon when all sides and angles are equal.


A rhombus is a parallelogram and quadrilateral with congruent sides.

Right triangle

A right triangle is s triangle with one right angle.

Scalene Triangle

A scalene triangle is a triangle with no congruent sides.


A trapezoid is a quadrilateral with only 1 pair of parallel sides.

Thank You!!!