Line Segments, Rays, and Angles 4.6A

What is a Line?

• a line goes on and on in both directions

• we show this by putting "arrowheads" on each end

What is a Segment?

• a segment is part of a line

• we show a line segment by putting dots on each end

• the dots show that the line has a starting point and a stopping point

What is a Ray?

• it begins at one point and continues on in one direction without end

• we show this by adding an arrowhead on one end and a dot on the other

What is a point?

• A point in geometry is a location. It has no size (no width, no length, and no depth)

• A point is shown by a dot

Multiple Choice

Which of these is a segment?

Multiple Choice

Which of these is a ray?

Multiple Choice

Which of these is a line?

Multiple Choice

Which of these is a point?

What is Parallel?

• Lines and segments that go in the same direction and stay the same distance apart are called parallel.

What are Intersecting Lines?

• When lines or segments cross, we call them intersecting lines.

What is Perpendicular?

• Intersecting lines or segments that form "square corners" are perpendicular.

Multiple Choice

Which of these are parallel lines?

Multiple Choice

Which of these are intersecting?

Multiple Choice

Which is perpendicular?

What are angles?

• Angles are formed where lines or segments intersect.

• Angles are also formed where at least two rays begin.

• An angle has a vertex and two sides.

More about angles.

• An angle is named by how open it is.

• The angle like the corner of a square is called a right angle.

Right Angles

• To show that an angle is a right angle, we can draw a small square in the corner.

Acute Angles

• Angles that are smaller than right angles are called acute angles.

Obtuse Angles

• Angles that are larger than right angles are called obtuse angles.

Multiple Choice

Which is an obtuse angle?

Multiple Choice

Which is an acute angle?

Open Ended

What is the difference between parallel lines and perpendicular lines?

Multiple Choice

Which is an obtuse angle?

Multiple Choice

What is the name of this ray?

• Ray AB

• Ray BA

• Ray ABC

• Ray AC

Parallel Lines

• Two or more lines continue in the same direction and maintain the same distance apart the entire length.

• They NEVER cross.

• Lines tx and yw are parallel lines.

• Think of railroad tracks

Line tx

Line Segment ab

Point

A single spot or an exact location