400mm
The longest diagonal of a 6 cm cube is: 10.39 cm
A decimeter (dm) is 10 centimeters (cm), so 400 dm would be larger.
90 cm/1 metre = 90 cm/100 cm = 90/100 = 0.9
1 inch = 2.54 cm Hence in 400 cm there are 400 /2.54 cm = 157.48 inches. 157.48 inches = 13 ft. 1.48 inches = 4 yds 1 dt 1.48 inches.
The area of the square cannot be 400 centimetres - it must be 400 square centimetres.If the area is 400 sq cm, then each side is sqrt(400) = 20 cm.