Question

If 10 millimeters (10 mm) equals 1 centimeter (1 cm), then 10 square millimeters (10 sq mm) equals: Select one: A 100 sq cm B. 0.10 sq cm C. 0.0010 sq cm D. 0.010 sq cm E. 1 sq cm

Answer 1

The correct answer is B. : 10 sq mm = 0.1 sq cm

Explanation:

It is just a matter of changing the units. The equivalence we need to know is 1cm = 10 mm. Also, we need to have in mind that we can write 10 sq mm as 10 mm*mm, because : 10 sq mm = 10 mm² = 10 mm*mm

Now we multiply two times by the fraction (1cm / 10 mm), which does not alter our measurement because the fraction is the same as multiplying by 1.

10 sq mm = 10 mm* mm = (10 mm*mm)*(1 cm / 10 mm)*(1 cm / 10 mm) = (10 mm*mm*cm*cm/ 10*10 mm*mm) =10/100 cm*cm = 0.1 cm² = 0.1 sq cm

Therefore, we have the equivalency : 10 sq mm = 0.1 sq cm