What is the basic unit of length in the metric system? What is the length of this line in: (i) Centimetres? (ii) Millimetres? (iii) Metres? Name the instruments that are used to measure the following. (i) Length of a soccer field (ii) Things that are not straight

Here are the answers to the questions:

1. The basic unit of length in the metric system is the meter.

2. To find the length of the line: The ruler shows markings in centimeters (cm), with each centimeter divided into 10 millimeters (mm). The line extends past the 3 cm mark by 3 small divisions.

   • (i) Centimetres? Step 1: Read the length from the ruler. The line ends at 3 cm and 3 mm. Step 2: Convert millimeters to centimeters. $1 cm = 10 \text{ mm}$ $3 mm = \frac{3}{10} cm = 0.3 \text{ cm}$ Step 3: Add the centimeter values. $3 cm + 0.3 cm = 3.3 \text{ cm}$ The length is $\boxed{3.3 cm}$.

   • (ii) Millimetres? Step 1: Convert the length in centimeters to millimeters. $1 cm = 10 \text{ mm}$ $3.3 cm = 3.3 \times 10 mm = 33 \text{ mm}$ The length is $\boxed{33 mm}$.

   • (iii) Metres? Step 1: Convert the length in centimeters to meters. $1 m = 100 \text{ cm}$ $3.3 cm = \frac{3.3}{100} m = 0.033 \text{ m}$ The length is $\boxed{0.033 m}$.

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

   • (i) Length of a soccer field A measuring tape (specifically a long one, or a surveyor's tape/wheel).
   • (ii) Things that are not straight A flexible measuring tape or a string/thread (which can then be measured with a ruler).