by Hilary Haubrich

9th Grade Geometry

Measuring Angles & Right Triangles

Hilary Haubrich
To obtain a downloadable copy of the worksheet that accompanies this bulletin board, click on the button below.

SUBJECT: 9th grade Geometry class

TOPIC: Measuring angles & Right triangles

INTERACTIVITY: There are several different designated spots on stage that an actor can stand. The student is to angle the spotlight so it would shine directly on the actor at a given spot. They will use the string attached to the spotlight to help them find the exact angle. The students will repeat this activity for each Velcro area, then complete the accompanying worksheet to compare the angles and create and discuss right triangles using the angles found.

DIRECTIONS FOR USE: Use the string to shine the spotlight onto each performer on stage. Measure and record the angle at which the light must be positioned for each performer before completing the accompanying worksheet. Please base your measurements as if the 90º mark on the protractor is, in fact, 0º. (Hint: Record your measurement reading’s complement.)

TIME: It should take about five minutes for a student to read the measurements of the angles for each actor. Twenty minutes should be allowed for worksheet completion.

SPECIAL CONSTRUCTION: I attached string (at a length that will reach the farthest point you would like measured) to a spotlight with packing tape. The bond must be strong enough that the string will not become loose and unattached while students measure angles. I positioned the performers in such a way that the students would be recording different angles. I made it a point to align two performers at the same angle, but in different positions. This way, while completing the worksheet, they can see that if right triangles were formed from these angles, they would be similar (not congruent). I also found a large, clear image of a protractor online. I printed it out on the same color paper as the background of my board and glued it. I then poked a large push pin through the spotlight (with the string attached) and then attached it on the protractor at the correct spot.

CREDIT: In my classroom, I require this activity to be completed by all students in class. Each student must turn in the completed worksheet with their own work. This assignment will be worth thirty points. This will factor into the students’ homework grades.

OTHER COMMENTS: This concept could be constructed in many different settings. The bulletin board could address any number of themes and still deal with the same lesson, such as the solar system or baseball. I wanted to use this setting because there are many students interesting in the performing arts, but this is a topic that is rarely integrated into subjects other than English. But I feel that this activity is good practice for measuring angles, finding an angle’s complement, forming right triangles, and using terminology that are incorporated in these lessons.

Hilary Haubrich
Fall 2006