Answer:
Hope it helps you ,hope it is clear. I used completing the square method.
Height of bottom box : -

Height of top box : -

Thus, height of two boxes =

Happy to help chodini!
Step-by-step explanation:
If a line segment AB of length 6.6cm is drawn, bisecting it perpendicularly at N, we have two lines AN and NB of length 3.3cm each.
Because the line is bisected perpendicularly, the angles formed at the point of bisection are 90 degrees.