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.

Trace the shape of the object on a grid of equal squares with sides of \(1\text{ cm}\).
Estimate the perimeter of each shape based on the grid.
Measure the perimeter of each shape using a ruler or a thread.
Record your estimation and measurement.
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

\(\text{Perimeter}=a+b+c+d\)

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.

Trace the shape of the object on a grid of equal squares with sides of \(1\text{ cm}\).
Estimate the perimeter of each shape based on the grid.
Measure the perimeter of each shape using a ruler or a thread.
Record your estimation and measurement.
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

\(\text{Perimeter}=a+b+c+d\)