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## Trigonometry and Clinometers

I know Clinometers are a pretty classic geometry activity to teach Trigonometry and Angles of Elevation, but I was really excited when the activity became relevant to my students.  I planned the activity and taught the necessary lessons.  We built clinometers using straws and protectors and practiced using them in the classroom.  The day finally came for us to go outside and measure items around the school that could not be measured with direct measurement.  I was in the main office that morning checking my mailbox and one of the Assistant Principals was showing off the new banners my school ordered to hang on the light posts  that line our school drive.  My high school is celebrating our 10th anniversary.  I asked the Assistant Principal who was going to hang the banners and if they had put any thought into it yet.  To my relief he said no.  I told him my class would be more than happy to help him.

I practically skipped to my classroom and couldn’t wait for Geometry to start.  I explained the new assignment to my class.  We needed to figure out how high to hang the banners and how long of a ladder we needed.  That was all the instruction they needed.  We spent the next 30 minutes outside seeing who could get the most precise measurements using our handcrafted devices.  I did not have to explain why someone would need to know how tall some random tree is or the height of our building.  They were hooked.  I convinced them we needed to let the janitor know by the end of the day so he could make sure we had a ladder at school that could work.  The students did a really good job calculating the height of the light poles, but the real discussion happened when we tried to decide the necessary height of the ladder.  The students wanted to know what would be a safe angle for the ladder to lean and the height of our janitor.  The more we discussed it, the more ideas and questions the students had, and I was ok with that.  We ended the lesson by turning in our discoveries to the janitorial staff.  I’m not sure if they used it or not (don’t tell my students), but my students felt a sense of pride in contributing to our campus.  The real reward came the next day when the students arrived at school and saw the banners hanging from the light poles.