Comparing Quantities | Class 7 Mathematics Notes

7.1 Equilateral Triangles

Equilateral triangles are those in which all three sides are equal in length, making them highly symmetric. Constructing an equilateral triangle with a given side length, such as 4 cm, can be done using a compass and ruler. Simply drawing the sides with a ruler may require multiple attempts to ensure all sides are equal. Using a compass simplifies this process: after drawing the base AB of length 4 cm, draw arcs of radius 4 cm centered at points A and B. The intersection of these arcs marks the third vertex C, ensuring AC = BC = AB = 4 cm. Joining these points forms the equilateral triangle. This method guarantees precision and efficiency in construction.

📊 Diagram: Stepwise construction of an equilateral triangle with base AB = 4 cm, arcs of radius 4 cm from A and B intersecting at C; See figure_5, figure_6, figure_7, figure_8.

🧪 Activity: Construct an equilateral triangle of side 4 cm using compass and ruler.

🔗 Connection: This section sets the foundation for constructing triangles with given sides, leading to the next section on constructing triangles with different side lengths.