Geometric Figures Polygons are two-dimensional closed geometric figures formed by line segments.

Two-Dimensional Figures Triangles have 3 sides and 3 angles. -

The sum of the measure of the inside angles of any triangles is always 180º. Angle + Angle + Angle = 180º

Scalene Triangle

No congruent sides or congruent angles

Isosceles Triangle

At least 2 congruent sides and at least 2 congruent angles

Right Triangle

Has a right angle (measure 90º)

Acute Triangle

All angles measure less than 90º

Equilateral Triangle

3 congruent sides and 2 congruent angles Obtuse Triangle

Has an angle that measures more than 90º

Quadrilaterals have 4 sides and 4 angles. -

The sum of the measure of the inside angles of any triangles is always 360º. Angle + Angle + Angle + Angle = 360º

Quadrilateral

Any closed figure with 4 sides

Rectangle

A parallelogram with 4 right angles

Parallelogram

Opposite sides are congruent and parallesl

Rhombus

A parallelogram with 4 congruent sides

Trapezoid

Exacly 1 pair of parallel sides

Square

A parallelogram with 4 right angles and 4 congruent sides. (A rhombus with 4 right angles) (A rectangle with 4 equal sides.)

Other Common Two-Dimensional Figures Pentagon

Hexagon

A polygon with 5 sides and 5 angles

A polygon with 6 sides and 6 angles

Octagon

A polygon with 8 sides and 8 angles

Three Dimensional Figures A 3-dimensional figure has length, width, and height. The surfaces may be flat or curved. A 3-dimensional figure with flat surfaces is called a polyhedron.

Prisms Triangular Prisms: -

5 faces (2 bases) 9 edges 6 vertices

Rectangular Prisms: -

6 faces (2 bases) 12 edges 8 vertices

Cubes: -

6 faces (2 bases) 12 edges 8 vertices

Pyramids Triangular Pyramid: -

4 faces (1 base – it’s a triangle) 6 edges 4 vertices

Rectangular Prisms: -

5 faces (1 base – it’s a rectangle) 8 edges 5 vertices