Geometry

Acute Angle

An angle less than 90 degrees but more than 0 degrees.

Acute Triangle

A triangle whose interior angles are all acute.

Altitude

Elevation above sea level or above the earth’s surface.

Angle

The space between two lines or planes that intersect.

Arc

A continuous portion of a circle.

Center

An area that is in the middle of some larger region.

Central

In or near an area.

Chord

A combination of three or more notes that blend harmoniously.

Circle

A plane curve with every point equidistant from the center.

Circumference

The length of the closed curve of a circle.

Complementary Angles

Two angles whose sum is a right angle.

Cone

A shape with a circular base and sides tapering to a point.

Congruent

Corresponding in character or kind.

Coordinate

Of equal importance, rank, or degree.

Coplanar

Lying in the same plane.

Cosine

Ration of the adjacent side to the hypotenuse of a right-angle triangle.

Cylinder

A surface generated by rotating a line around a fixed line.

Degree

A specific identifiable position in a continuum or series.

Diameter

The length of a straight line through the center of a circle.

Distance

The property created by the space between two objects.

Equiangular Triangle

A three-sided regular polygon.

Equilateral Triangle

A three-sided regular polygon

Equivalent

Being essentially comparable to something.

Exterior Angle

The supplement of an interior angles whose sum of a polygon.

Geometric Mean

The mean of n numbers expressed as the n-th root of their product.

Inscribed

Written on or in a surface.

Isosceles Triangle

A triangle with two equal sides.

Measure

Determined the dimensions of something or somebody.

Median

Relaxing to or situated in or extending toward the middle.

Midpoint

A point equidistant from the ends of a line or the extremities of a figure.

Obtuse Angle

An angle between 90 and 180 degrees.

Obtuse Triangle

A triangle that contains an obtuse interior angle.

Parallel

Being everywhere equidistant and

Parallelogram

A quadrilateral whose opposite sides are parallel and equal.

Perimeter

A line enclosing a plane area.

Polygon

A closed plane figure bounded by straight sides.

Polyhedron

A solid figure bounded by plane polygons or faces.

Prism

A polyhedron with two congruent and parallel faces.

Proportion

Relation with respect to comparative quantity or magnitude.

Pyramid

A polyhedron having a polygonal base and triangular sides.

Quadrilateral

A four-sided polygon.

Radius

A straight line from the center to the perimeter of a circle.

Ratio

Relation with respect to comparative quantity or magnitude.

Ray

A group of nearly parallel lines of electromagnetic radiation.

Rectangular

Having four right angles.

Regular Polygon

A polygon of all sides and all angle are equal.

Rhombus

A parallelogram with four equal sides.

Right Angle

The 90 degree angle between two perpendicular lines.

Right Triangle

A triangle with one right angle.

Scalene Trinangle

A triangle with no two side of equal length.

Secant

A straight line that intersects a curve at two or more points.

Sector

A particular aspect of life or activity.

Segment

One of several parts that fit with others to make a whole.

Similarity

The quality of being alike.

Sine

Ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle.

Slope

Be at an angle.

Sphere

A round three-dimensional closed surface.

Square

A polygon with four equal sides and four right angles.

Sum

A quantity obtained by the addition of a group of numbers.

Surface Area

The extent of a two-dimensional surface enclosed within a boundary.

Tangent

A line that touches a curve at only one point.

Transformation

The act of changing in form or shape or appearance.

Transversal

Extending or lying across.

Trapezoid

A quadrilateral with one pair of parallel sides.

Triangle

A three-sided polygon.

Unequal

Poorly balanced or matched in quantity or value or measure.

Vertical Angle

Either of two equal and opposite angles formed by the intersection of two straight lines.