What would the height of this Pyramid be

What is being taught in the context of this question?

My guess is that they expect you to use the average of each measurement, assuming all the angles and all the sides are really equal. (Is the context about using real-life measurements in that way?) Then the question is, what formulas do you know that you can put these averages into?
 
The best way I thought wbout doing this is taking the average of the four sides which would be 755.78 and half that and use it as a theortical base apothem multiple by tan and the average angle of the four sides to get the approx height since the base of the pyramid covers more than 13.1 and the sides vary at modt only 3 inches between the longest and shortes then by knowing the apporx height taking that calculated height and divded by tan and slope anlge of each individual side to get the actual base apothem of each side.Then use pythogream theorem to get the slant height
 
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