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Understanding Angles in Geometry
Jul 14, 2024
Geometry: Understanding Angles
Introduction
Continuation of the Geometry series.
Today’s topic: Angles.
Prerequisite knowledge: Points and lines.
Parallel Lines
Two lines in the same plane pointing in the same direction.
Never cross, even if extended infinitely.
Term:
Parallel
lines.
Intersecting Lines
When lines are nudged and cross at a point.
The crossing point:
Intersection
.
Lines crossing form
angles
(spaces/shapes between intersecting lines).
Four angles are formed at the intersection.
Example of naming angles:
∠DPB
∠APD
.
Shorthand notation: Use the
angle symbol (∠)
.
Naming Angles with Arcs
Imagining a line segment rotating around an intersection point forming a circle or an arc.
The arc represents the angle formed.
Simplified naming:
Example:
Angle A
(∠A).
Drawing a small arc around the intersection.
Perpendicular Lines & Right Angles
Adjusting lines to form square corners.
Perpendicular
lines form square corners called
right angles
.
Right angle symbol
: A small square.
Types of Angles
Acute angles
: Less than right angles.
Obtuse angles
: Greater than right angles.
Straight angles
:
When rays point in opposite directions.
Looks like a straight line.
Complementary and Supplementary Angles
Complementary angles
: Two angles that form a right angle.
Supplementary angles
: Two angles that form a straight angle.
Summary of Key Terms
Parallel lines
: Lines that never cross.
Intersection
: The point where lines cross.
Angles
: Space between intersecting lines.
Arc
: Part of a circle representing an angle.
Perpendicular lines
: Lines forming right angles.
Right angles
: Square corner angles.
Acute angles
: Less than right angles.
Obtuse angles
: Greater than right angles.
Straight angles
: Looks like a straight line.
Complementary angles
: Combine to form a right angle.
Supplementary angles
: Combine to form a straight angle.
Next Steps
Next video: Measuring angles.
Learn more at
www.mathantics.com
.
📄
Full transcript