Q4 of 805 Page 17

Using ruler and compasses only, construct an Δ ABC, given base BC = 7 cm, ∠ABC = 60° and AB+AC=12 cm.

The steps of the required construction are:

1) Draw a line segment BC=7cm. Using a protractor, draw ∠CBD=60°. Join and extend BD.



2) Taking B as the center and radius=12cm, draw an arc, intersecting extended BD at point P. Join PC.



3) Taking P as the center and radius greater than , draw arcs on each side of PC. Now, taking C as the center and same radius, draw arcs, intersecting the previous arcs at points Q and R. Join and extend QR. Extended QR intersects line segment DB at point A. Join AC.



4) ∆ABC is the required triangle.


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Construct a triangle whose perimeter is 6.4 cm, and angles at the base are 60° and 45°.

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Using ruler and compasses only, construct a Δ ABC from the following data :

AB+BC+CA=12 cm, ∠B = 45° and ∠C = 60°.