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Question
Ruler and compasses may be used in this question. All construction lines and arcs must be clearly shown and be of sufficient length and clarity to permit assessment.
- Construct a ΔABC, in which BC = 6 cm, AB = 9 cm and angle ABC = 60°.
- Construct the locus of all points inside triangle ABC, which are equidistant from B and C.
- Construct the locus of the vertices of the triangles with BC as base and which are equal in area to triangle ABC.
- Mark the point Q, in your construction, which would make ΔQBC equal in area to ΔABC, and isosceles.
- Measure and record the length of CQ.
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Solution
Steps of construction:
- Draw a line segment BC = 6 cm.
- At B, draw a ray BX making an angle 60 degree and cut off BA = 9 cm.
- Join AC. ABC is the required triangle.
- Draw perpendicular bisector of BC which intersects BA in M, then any point on LM is equidistant from B and C.
- Through A, draw a line m || BC.
- The perpendicular bisector of BC and the parallel line m intersect each other at Q.
- Then triangle QBC is equal in area to triangle ABC. m is the locus of all points through which any triangle with base BC will be equal in area of triangle ABC.
On measuring CQ = 8.4 cm.
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(i) Construct a triangle ABC with BC = 6 cm, ∠ABC = 120° and AB = 3.5 cm.
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