She need 3 bags since the area of the triangle is base x height /2
Area 20*6=120
120/2=60
60/20= 3 since each bag covers 20m^2
Surface area of a cube = 6l²
Now given length = l = 8 mm
= 6*8² = 6*64 = 384 mm².
Thank you !!
4 (i literally had to think about this cause i thought it was too easy )