Axiom

A mathematical statement accepted as true without proof.

Proposition

A mathematical statement that can be proved or disproved.

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Geometry. (2015). In A. H. Blackwell & E. Manar (Eds.), UXL Encyclopedia of Science (3rd ed.). UXL. https://link.gale.com/apps/doc/CV2644300494/SUIC?u=61_alls&sid=SUIC&xid=2e956e8b

   

Congruent

The same shape and size, but we are allowed to flip, slide or turn.

Angles are congruent when they are the same size (in degrees or radians).

Sides are congruent when they are the same length.

Definition of Congruent. (n.d.). Retrieved from https://www.mathsisfun.com/definitions/congruent.html

Similar

Two shapes are Similar when one can become the other after a resize, flip, slide or turn.

Similar. (n.d.). Retrieved from https://www.mathsisfun.com/geometry/similar.html

 

QED

Short for the Latin phrase "quod erat demonstrandum" meaning "that which was to be demonstrated"

Used at the end of a proof to show it is completed.

Also written Q.E.D.

QED Definition (Illustrated Mathematics Dictionary). (n.d.). Retrieved from https://www.mathsisfun.com/definitions/qed.html

   

Proof:

In mathematics, along with the sciences, a proof is a logical argument demonstrating that a specific statement, proposition, or mathematical formula is true. It consists of a set of assumptions, or premises, which are combined according to logical rules (called rules of logic), to establish a valid conclusion. This validation can be achieved by direct proof that verifies the conclusion is true, or by indirect proof that establishes that it cannot be false.

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Schueller, R. (2014). Proof. In K. L. Lerner & B. W. Lerner (Eds.), The Gale Encyclopedia of Science (5th ed.). Gale. https://link.gale.com/apps/doc/CV2644031810/SUIC?u=61_alls&sid=SUIC&xid=a071f2fa

   

Bisector

The line that divides something into two equal parts.You can bisect line segments, angles, and more.

Definition of Bisector. (n.d.). Retrieved from https://www.mathsisfun.com/definitions/bisector.html

Chord

A line segment connecting two points on a curve. For example the line segment connecting two points on a circle's circumference is a chord. Does not pass through the centre of a circle.

Definition of Chord. (n.d.). Retrieved from https://www.mathsisfun.com/definitions/chord.html

Circle

A circle is a closed curved line on which every point is equally distant from a fixed point within it.

A diagram of a circle. Point C is the center; AC is the radius; BD is the diameter; AC, BD, and DE are all chords; and the straight line outside the circle is a tangent.

Circle [Article]. (2008). L. C. Bruno (Ed.), Math & Mathematicians: The History of Math Discoveries Around the World. UXL. https://link.gale.com/apps/doc/CV2210051480/SUIC?u=61_alls&sid=bookmark-SUIC&xid=eb9df958

Circumference

The distance around a circle.

Encyclopædia Britannica. (n.d.). Mathematics at a glance. Britannica School. Retrieved October 7, 2021, from https://school.eb.com.au/levels/middle/article/mathematics-at-a-glance/623715#

Diameter

A straight line from one side of a circle to the other side that passes through the centre.

Encyclopædia Britannica. (n.d.). Mathematics at a glance. Britannica School. Retrieved October 7, 2021, from https://school.eb.com.au/levels/middle/article/mathematics-at-a-glance/623715#

Parallel

Extending in the same direction and at an equal distance from one another. Parallel lines never meet.

Encyclopædia Britannica. (n.d.). Mathematics at a glance. Britannica School. Retrieved October 7, 2021, from https://school.eb.com.au/levels/middle/article/mathematics-at-a-glance/623715#

Radius

A straight line from the centre of a circle or sphere to any point on the outer edge.

Encyclopædia Britannica. (n.d.). Mathematics at a glance. Britannica School. Retrieved October 7, 2021, from https://school.eb.com.au/levels/middle/article/mathematics-at-a-glance/623715#

Polygon

A closed geometric figure with at least 3 sides.

Basic Math Glossary-P.  Basic-mathematics.com. Retrieved from https://www.basic-mathematics.com/basic-math-gloss ary-P.html

Sector

A part of a circle bounded by two radii.

Basic Math Glossary-S.  Basic-mathematics.com. Retrieved from https://www.basic-mathematics.com/basic-math-gloss ary-S.html

Segment

A line with a beginning point and an endpoint.

Basic Math Glossary-S.  Basic-mathematics.com. Retrieved from https://www.basic-mathematics.com/basic-math-gloss ary-S.html

Tangent line

A tangent line just touches a curve at a point, matching the curve's slope there.

Tangent and Secant Lines. (n.d.). Retrieved from https://www.mathsisfun.com/geometry/tangent-secant -lines.html

   

Equilateral triangle

a triangle in which all three sides are of equal length

 

Isosceles triangle

a triangle with at least two sides of equal length

 

Right triangle

a triangle in which one of its angles measures 90 degrees (a right angle)

 

Scalene triangle

a triangle in which each side is of a different length

 

A chart shows the basic types of triangles.

Encyclopædia Britannica, Inc.

 

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Triangle. (2008). In L. C. Bruno (Ed.), Math & Mathematicians: The History of Math Discoveries Around the World. UXL. https://link.gale.com/apps/doc/CV2642820019/SUIC?u=61_alls&sid=bookmark-SUIC&xid=26ff5e1e