Friday, April 5, 2019

Lines, Rays, and Angles

Lines, Rays, and Angles

Our geometry unit is in full swing! Here are some of the vocabulary terms that we use.

point is an exact position on a plane surface.


line is a collection of points along a straight path with no end points. 


line segment is a part of a line that contains every point on the line between its end points. 



ray is a line with a single end point that goes on and on in one direction.



Parallel Lines are two lines that remain the same distance apart at all times and never intersect.


Perpendicular Lines are two lines that intersect and from right angles. 


Intersecting Lines meet or cross each other.



A figure is symmetric (or has symmetry) if it can be folded on a line to form two equal (congruent) halves that fit on top of each other.

Image result for symmetryImage result for symmetry

Line of symmetry is the fold line of a symmetrical figure. A figure can have one, many, or no lines of symmetry.

Image result for symmetry

Related image

An  angle is the intersection of two rays with a common vertex or endpoint. An angle measures the amount of turn of the rays.



There are four types of angles that we have learned about.

An acute angle is an angle whose measure is less than 90°.

Image result for acute angle Image result for acute angle

right angle is an angle whose measure is 90°.

Image result for right angle Image result for right angle

An obtuse angle is an angle whose measure is more than 90°, but less than 180°.

Image result for obtuse angle  Image result for obtuse angle

straight angle is an angle whose measure is 180°.

Image result for straight angle Image result for straight angle

Remember that an angle is named using three letters, where the middle letter corresponds to the vertex of the angle.  The angle below is ∠ABC or ∠CBA.   If it is perfectly clear which angle is being named, an angle may be referred to by its vertex letter alone, such as B.

Image result for angle ABC

Here are a couple of fun website that allows you to play around with angles:

Angles

Name that Angle

Check out our angle song:

Angle Song

Watch this video to get a better understanding of the differences between these geometry terms.

Geometry Terms

Here are some ways to practice the geometry terms:

Geometry Term Practice

Lines, line segments, and rays practice

Ask your kiddo to show you the dance moves we came up with for these terms.

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