Return to Mathematics IndexSingleton, Earl M. III Daniel Hale Williams SchoolObjectives1) Students will be able to identify the names of angles formed when

parallel lines are intersected by a transversal. 2) Students will be able to

identify the measurement of angles formed when parallel lines are

intersected by a transversal.

Equipment and Materials

Overhead Projectorr One plastic overlayy Three transparenciess: Crayonss Four page worksheett

Materials

Recommended Strategies:

Pass out the four page worksheet which contains the vocabulary and three other

pages with parallel lines intersected by a transversal. Begin the lesson by

showing the parallel lines on the overhead projector. "What are these lines?"

"What are other examples of parallel lines in this room?" Have a student define

parallel lines. Next, show the illustration of the parallel lines intersected

by a transversal on the overhead projector. "What is created when a transversal

intersects the parallel line?" -- angles. Have the class turn to the second

sheet and identify adjacent, supplementary, and straight angles -- all of which

equal 180 degrees. Have them color code the straight angle green and place a

green arch over the straight angle to illustrate a semicircle. Call on two

students to come up. Position them side by side, and ask the class the

following question: What would you call neighbors who, lived right next to each

other on the same side of the street? They would be next door neighbors and in

math we call them adjacent angles. They share a common ray and vertex. Next,

have the class turn to the third page of the worksheet and label the top of the

page corresponding angles. Begin to identify congruent corresponding angles and

color code each pair of corresponding angles a different color. They will have

four different pairs of corresponding angles -- each pair having a different

color. Proceed to the fourth page and have the class label this page alternate

exterior and alternate interior angles. Again, have them color code each pair

of angles. Solicit the definition of interior and exterior. Place a group of

students in a circle and put one person in the middle of the circle. The

teacher should stand outside of the circle. Ask questions about the

relationship of the teacher to the person on the inside of the circle. This

activity will help reinforce the concept of interior/exterior relationship. In

order to further develop the concept of alternate, have the person on the inside

of the circle alternate jumping up and down with the teacher. Go to the board

to illustrate alternate exterior and interior angles. Lead them to discover

that they are alternate exterior angles because they are on the opposite side of

the transversal and on the outside of the parallel lines. Continue by

demonstrating that alternate interior angles are on the inside of the parallel

lines and on alternate sides of the transversal. After reviewing all the terms,

assign a measurement to one of the angles and have the class determine the

measurement of the other angles and justify their answer.