## Perimeter

 10.1 Perimeter

 Definition The total length around an enclosed area.

 Example Determine the perimeter of the following shape. \begin{aligned} &\space\text{Perimeter} \\\\&=PQ+QR+RS+ST \\&\quad +TU+UV+VW+WP \\\\&=4+3+4+3+4+9 \\&\quad+12+9 \\\\&=48\text{ cm}. \end{aligned}

Estimate the perimeter accurately:

Steps to estimate the perimeter of various shapes.

1. Trace the shape of the object on a grid of equal squares with sides of $$1\text{ cm}$$.
2. Estimate the perimeter of each shape based on the grid.
3. Measure the perimeter of each shape using a ruler or a thread.
4. Record your estimation and measurement.
5. Compare the estimated value with the measured value to evaluate the accuracy of your estimation.

• The accuracy of estimated perimeter can be evaluated by comparing the estimated value with the measured value.
• The smaller the difference between the values of estimated perimeter and measured perimeter, the more precise the estimated value.

The formulae for the perimeter of various shapes:

(i) The perimeter of a triangle

 $$\text{Perimeter}=a+b+c$$

(ii) The perimeter of a paralellogram

 $$\text{Perimeter}=2a+2b$$

(iii) The perimeter of a kite

 $$\text{Perimeter}=2a+2b$$

(iv) The perimeter of a trapezium

 $$\text{Perimeter}=a+b+c+d$$

## Perimeter

 10.1 Perimeter

 Definition The total length around an enclosed area.

 Example Determine the perimeter of the following shape. \begin{aligned} &\space\text{Perimeter} \\\\&=PQ+QR+RS+ST \\&\quad +TU+UV+VW+WP \\\\&=4+3+4+3+4+9 \\&\quad+12+9 \\\\&=48\text{ cm}. \end{aligned}

Estimate the perimeter accurately:

Steps to estimate the perimeter of various shapes.

1. Trace the shape of the object on a grid of equal squares with sides of $$1\text{ cm}$$.
2. Estimate the perimeter of each shape based on the grid.
3. Measure the perimeter of each shape using a ruler or a thread.
4. Record your estimation and measurement.
5. Compare the estimated value with the measured value to evaluate the accuracy of your estimation.

• The accuracy of estimated perimeter can be evaluated by comparing the estimated value with the measured value.
• The smaller the difference between the values of estimated perimeter and measured perimeter, the more precise the estimated value.

The formulae for the perimeter of various shapes:

(i) The perimeter of a triangle

 $$\text{Perimeter}=a+b+c$$

(ii) The perimeter of a paralellogram

 $$\text{Perimeter}=2a+2b$$

(iii) The perimeter of a kite

 $$\text{Perimeter}=2a+2b$$

(iv) The perimeter of a trapezium

 $$\text{Perimeter}=a+b+c+d$$