The way this assignment is formatted, it is meant to be outside measuring inaccessibly tall. The students already had a very good understanding of the primary trig ratios and how to use them, as they had already taken Foundations and Pre-Calculus 10. We did a quick review of sine, cosine and tangent. If I had a group of students who were unfamiliar with the ratios, I would take a day or two to introduce the ratios. A good understanding of the trig ratios is necessary for them to be able to do a good job with this assignment.
Since we were using apps on the iPad, I took a good 20-30 minutes to explain the logistics behind how to hold the iPad, etc. in order to get accurate measurements with the Tape Measure app and the Clinometer app.