Page 2 - Lesson Note 2- ch 11 Triangle construction(Contruction)

Steps of Construction:

Step 1: Draw the base BC which is equal to a cm and at point B make an∠XBC = x°.
Step 2: From ray, BX cut the line segment BD which is equal to AB – AC.
Step 3: Join DC and draw the perpendicular bisector of DC.
Step 4: This perpendicular bisector intersects BX at a point A. By joining A to C we get the
required triangle i.e. ∆ABC.
Case (ii): If AB < AC that is AC – AB is given.
Steps of Construction:

Step 1: Draw the base BC and at point B make an ∠XBC.
Step 2: From ray, BX cut the line segment BD which is equal to AC – AB from the line BX by
extending it on opposite side of line segment BC.
Step 3: Join DC and draw the perpendicular bisector of DC.
Step 4: Let PQ intersect BX at A and by joining A to C, we get the required triangle ∆ABC.
Construction 3: How to construct a triangle if its perimeter and two base angles are
given?

Given the base angles, say ∠ B and ∠ C and BC + CA + AB, you have to construct the triangle
ABC.

Steps of Construction:
Step 1: Draw a line segment XY = BC + CA + AB.
Step 2: Make ∠LXY = ∠B and ∠MYX = ∠C.
Step 3: Now bisect ∠ LXY and ∠ MYX. These bisectors will intersect at a point A.

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