numerous students job-related with angle in mathematics class but have no clue just how to name those angles. Together a math tutor, I confront many students that are totally lost in terms of angles. What is an angle? 2 rays that share the very same endpoint kind an angle.

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The symbol because that angle is . Exactly how do us name angles in geometry?

us name angle in three different ways:

(1) We deserve to name angle by using THREE funding letters like: alphabet or DEF. The center letter is referred to as the peak of the angle. The above angles are check out "angle ABC" and also "angle DEF." This leads united state to the second method we deserve to name angles.

(2) We have the right to name angles by using the vertex. Because that example, ABC, can likewise be referred to as angle B; the same uses to DEF (we can speak to angle DEF angle E). That course, if there"s an ext than one edge sharing the exact same vertex this would be confusing!

(3) us can likewise name an angle by placing any type of number or symbol at the crest in the inner of the angle. So, angles can also be referred to as angle 1 or edge 2 or angle 4, etc.



The over angle have the right to read three ways:

(1) angle abc (2) angle B (3) angle 1

Sides abdominal and AC the the given angle room actually rays. Why rays? due to the fact that they extend out come infinity in one direction. Once two rays satisfy at a vertex, they type an angle.

In geometry, you will certainly come throughout postulates and theorems necessary for geometric proofs.

A theorem is a statement that deserve to be showed to be true.

A postulate is a statement the is presume to be true without proof. Every this becomes part of your new geometry vacabulary. Ns will get in detail about postulates and theorems in future lessons title GEOMETRIC PROOFS.

heat Segments: The line segment of a line is the span between two endpoints. Remember, a line itself is infinite, and also a heat segment is a finite part of that. Realistically, something you attract on paper is a line segment due to the fact that it cannot walk on forever!

The degree measure the an edge is the amount of rotation indigenous one side of the angle to various other side.

What is a rotation?

A rotation is a movement of things in a one motion. Think about the planet going approximately the Sun, a journey that takes one year come complete. An edge is a measure of how far around something has gone.

Perpendicular Line: Perpendicular lines space lines that accomplish or cross to form a best angle. A right angle same 90 degrees.

A perpendicular symbol is simply an upside down resources letter T. It looks choose this:


adjacent angles: two angles are surrounding if they have actually the very same VERTEX, re-superstructure ONE SIDE and do not overlap.



The above symbol matches our definition of adjacent angles.

A couple of more definitions and also that"s it for Geometry 1.3:

Congruent Segment: as soon as two line segments re-superstructure the exact same length, castle are said to it is in CONGRUENT or equal.

Say line segment ab = 10 inches and also line segment CD = 10 inches, climate line segment abdominal muscle is congruent or equal to heat segment CD.

The symbol because that CONGRUENCE is and so, the above can be created this way:

us write: ab CD. This way "line segment abdominal muscle is congruent to line segment CD."

Midpoint of heat Segment: The midpoint the a heat segment divides the segment into TWO segment of same length.


heat segment abdominal is divided by the midpoint M. The street from A to M is 20 feet and also the distance from BM is 20 feet. Climate line segment am = line segment BM.

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any line or segment the passes through the midpoint that a line segment, bisects (cuts) the heat segment.