Convert $20{\text{cm}}^{\text{2}}$ into ${\text{km}}^{\text{2}}$  

To convert 20cm squared into square kilometers (km²), we need to follow the appropriate unit conversions between centimeters, meters, and kilometers.

Step-by-Step Conversion

First, let’s start by converting square centimeters (cm²) into square meters (m²).

• 1 centimeter (cm) is equal to 10^-2 meters (m).
• Since we are working with square units, we square this value to convert 1 cm² into m²: 
  1 cm² = (10^-2)² m² = 10^-4 m².

So, to convert 20cm squared into meters squared:

• 20 cm² = 20 × 10^-4 m² = 0.002 m².

Next, let's proceed to convert meters squared (m²) into kilometers squared (km²). To do so:

• 1 kilometer (km) is equal to 10³ meters (m).
• To convert m² into km², we square this value: 
  1 m² = (10³)² km² = 10⁶ km².

Therefore, converting 20 cm² (which is equal to 0.002 m²) into kilometers squared involves:

• 0.002 m² = 0.002 × 10^-6 km² = 2 × 10^-9 km².

Final Result

The conversion of 20cm squared into square kilometers (km²) is:

• 20 cm² = 2 × 10^-9 km².

In conclusion, to convert 20cm squared into km², the result is 2 × 10^-9 km².