Convert 25cm to mm.

Here are the answers to the questions:

3. Name the instruments that are used to measure the following.

   • (iii) Distance that you have travelled in a vehicle An odometer.

4. Convert 25 cm to mm. Step 1: Recall the conversion factor between centimeters and millimeters. $1 cm = 10 \text{ mm}$ Step 2: Multiply the given length in centimeters by the conversion factor. $25 cm = 25 \times 10 mm = 250 \text{ mm}$ The conversion is $\boxed{250 mm}$.

5. Convert 30 km to m. Step 1: Recall the conversion factor between kilometers and meters. $1 km = 1000 \text{ m}$ Step 2: Multiply the given length in kilometers by the conversion factor. $30 km = 30 \times 1000 m = 30000 \text{ m}$ The conversion is $\boxed{30000 m}$.