A glass Roof Lantern in the shape of a pyramid has a rectangular base CDEF and its apex is at B as shown - Leaving Cert Mathematics - Question 7 - 2016

Using the relationship of the angle of elevation:

1. From triangle ABC:

   Using the tangent again: $\tan(60°) = \frac{|AB|}{x}$

2. Thus, substituting |AB| = 3 m:

   $x = \frac{|AB|}{\tan(60°)} \approx \frac{3}{\sqrt{3}} = \sqrt{3} m$

3. Therefore, the length of the side of the base is √3 m where a is 3.