Question

Arrange in ascending order:

• A. 100 mm
• B. 20 cm
• C. 500 m
• D. 2 km

Answer 1

Since the measurements are in different units, let us first convert them all to one unit and then compare.
1 km = 1000 m
$\Rightarrow$2 km = 2 $\times$ 1000 m = 2000 m
1 m = 100 cm
$\Rightarrow$ 2000 m = 2000 $\times$ 100 cm = 2,00,000 cm
1 cm = 10 mm
$\Rightarrow$ 2,00,000 cm = 2,00,000 $\times$ 10 mm = 20,00,000 mm
Similarly, 500 m = 500 $\times$ 100 cm = 50,000 $\times$ 10 mm = 5,00,000 mm.
Also, 20 cm = 20 $\times$ 10 mm = 200 mm.
Since 100 mm $<$ 200 mm $<$ 5,00,000 mm $<$ 20,00,000 mm, we must have
100 mm $<$ 20 cm $<$ 500 m $<$ 2 km.