Perimeter

Summary and Exam Tips for Perimeter

Perimeter is a subtopic of Geometry, which falls under the subject Mathematics in the Edexcel Lower Secondary curriculum. The perimeter of a shape is the total length of its boundary. For rectangles and squares, the perimeter is calculated by adding the lengths of all four sides. Specifically, for a rectangle, the formula is $\text{Perimeter} = 2 \times \text{Length} + 2 \times \text{Breadth}$, while for a square, it is $\text{Perimeter} = 4 \times \text{Length}$.

When dealing with composite figures, which are combinations of various 2D shapes, the perimeter is found by summing all the individual side lengths. This involves adding up all the lengths and breadths of the composite figure.

For a circle, the perimeter is referred to as the circumference. The formula for the circumference is $C = 2\pi r$, where $r$ is the radius of the circle and $\pi$ is approximately 3.14 or $\frac{22}{7}$. Understanding these formulas and concepts is crucial for solving problems related to perimeter in geometry.

Exam Tips

• Memorize Key Formulas: Ensure you remember the formulas for the perimeter of rectangles, squares, and circles. Practice using $\text{Perimeter} = 2 \times \text{Length} + 2 \times \text{Breadth}$ and $C = 2\pi r$.

• Break Down Composite Figures: When dealing with composite figures, break them down into simpler shapes, calculate individual perimeters, and then sum them up.

• Visualize the Problem: Drawing diagrams can help you better understand the problem and ensure you account for all sides when calculating the perimeter.

• Check Units: Always ensure that all measurements are in the same unit before calculating the perimeter.

• Practice with Real-Life Examples: Apply perimeter concepts to real-world scenarios, like fencing a garden, to better grasp their practical applications.