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WEEK 5

TOPIC: Constructions

Content:

• Guidelines for constructions
• Constructions of basic angles
• Construction of triangles with given sides and angle.
• Bisection of basic angles

GUIDELINES FOR CONSTRUCTIONS

When making constructions, the following guidelines should be followed.

1. A short pencil of about 3 inches should be fixed on the pair of compasses when constructing to avoid any obstruction when turning your compass round to draw arcs.
2. Ensure that the pivot of your pair of compasses is tight to avoid unwanted shift when carrying out your constructions.
3. To ensure that your lines and points are as fine and accurate as possible make use of a hard pencil with a sharp point.
4. Before making the actual construction, make a rough sketch of the problem under consideration. This will make the construction of the actual problem easy.
5. Leave all your arcs and construction lines visible. Do not clean any arc that leads you to your final result.
6. Double lines and arcs in constructions are not allowed, hence clean up all double arcs and lines neatly and re-draw.

Bisecting of Angles

To bisect the angle ABC,

Step 1: –Measure a length of about 2.5cm with your pair of compasses. Fix pin at B and draw an arc to cut the two line AB and BC that formed the angle. Cut the arc at x and y.

Step 2: – Fix pin at x and draw an arc and at y and draw another arc both to meet at z.

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