Quandaries and Queries


I'm helping my daughter build a pyramid,it needs to be 30cm in height. I have cut out four pieces at 30 deg angles. When I went to join up the pieces it did not fit. I re-check my measuments and found that they were correct. Do I need to cut two pieces smaller so they can match up? Did I cut them at the wrong angles. My base is also 30cm, is that my problem?
Thanks for your help


Hi Marc,

Finding the correct angle will just make the work harder. I would make each triangle for the side of the pyramid by first measuring its base to be 30 cm, and its two other sides to have length 15 sqrt(6) cm, which is about 36.74 cm. (That makes the height of each triangle to be 15 sqrt(5), which is the correct slant height of a square pyramid whose base is 30cm on each side.


Hi Marc,

One way to find the value of 15 sqrt(6) cm that Chris uses can be found in an answer Penny gave to a similar question by Jacob.



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