Something that took place at school

It was just an ordinary school day except that I had a math project to do that day after school.It was about finding the diameter of the school crest which was outside the auditorium. When my group found out that was our aim, we were awestruck. How are we able to find out the diameter of the crest which was impossible to reach or touch it? But after thinking for quite a while, we decided to take a picture of one of us with the school crest in the background at the fourth floor. We then measured the distance from the camera to the boy and the boy to the school crest as accurately as possible. Taking the distance from camera to the boy was pretty simple except for the fact that the measuring tape we brought was not long enough as it was only 3metres . Next was the hard part. We went down and found out we had to measure the length from the library then across the pond and to the estimated part of the floor where the crest was above. Luckily, we managed to borrow a longer measuring tape. One of my group member then slowly walk to the edge of the library, careful not to fall into the pond. With help from another member of the group, we managed to get the measurement from the edge of the library across the pond.We then measured the rest of the length with ease. After that we tried to work out the ratio of the boy's height and the school crest to find out the diameter of the school crest. After a long period of brain juice used, we finally figured out the diameter of the school crest.
Since the math project deadline is not out yet, I cannot tell you what the answer is.