Lets split the box in pieces and then add:
top = 20*15 = 300
sidesA = 2*20*9 = 360, is multiplied by 2 cause there are 2 sides like this
sidesB = 2*9*15 = 270, is multiplied by 2 cause there are 2 sides like this
so in total we have:
total = 300 + 360 + 270 = 930 cm^2
if we express this quantity in mm^2 we have:
<span>1cm² = 100 mm²</span>total = 930*100 = 93000 mm^2
so if the tiles are 5 mm^2 we need:
total tiles = <span>93000/5 = 18600
we need 18600 tiles of 5 mm^2</span>
So I'm not totally sure but I got -15.32
So sorry if it's wrong!!
20 ft because the shadow would be 3/2 of the height. 9 is 3/2 of 6 so the height would be 20 bc 30 is 3/2 of 20
