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1. Chapter 11 Class 9 Constructions
2. Serial order wise
3. Ex 11.1

Transcript

Ex 11.1, 5 Construct an equilateral triangle, given its side and justify the construction. Let equilateral triangle be ABC Draw AB = 5 cm Taking A and B as centers, radius = AB = 5 cm, draw two two arcs intersecting each other at A Join AB and AC Thus Δ ABC is our required triangle Ex 11.1, 5 Construct an equilateral triangle, given its side and justify the construction. Let’s assume side of equilateral triangle is 5.5 cm In an equilateral triangle, all sides are equal So, our triangle looks like Let’s construct it Steps of construction 1. Draw a line segment AB of length 5.5 cm 2. Taking 5.5 cm as radius, and A as center, draw an arc. 3. Taking 5.5 cm as radius, and B as center, draw another arc. 3. Taking 5.5 cm as radius, and B as center, draw another arc. Thus, Δ ABC is the required equilateral triangle Justification By construction, AB = AC = BC Since all sides are equal ∴ ∆ABC is an equilateral triangle. Thus, the Construction is justified.

Ex 11.1 