How tall is that house?

We’re limited today by not being able to cross the road to measure to the base of the building.

We used a home made clinometer today to figure out how tall he house is across the street. We made our clinometer by taping a string to the middle of a protractor and tied a washer to the end of the string. When the clinometer is horizontal, the string falls vertically and hits the 90 degree mark. When we tip the clinometer up toward the peak of the roof, we measure the angle by looking at where the string falls, and comparing that number with 90.

We walked backward (measuring that distance) and then took another angle measurement to the roof.

We need to know the height up to the measurer’s eyes too.

And then we can calculate the height of the building

We use our understanding of supplementary angles and sine law and the sine function to do it.