CONSTRUCTION OF PARALLEL LINES USING RULER AND SET SQUARE ONLY

CONTENT

i.              To draw parallel lines (Horizontally) using a ruler and set-square only.

ii.             To draw parallel lines (Non-horizontal) using a ruler and set-square only.

iii.            Application of construction. Plane figure.

i.              Drawing parallel lines (Horizontally using a ruler and set-square only.

                (a) Guidelines for constructions.

In geometry, to construct a figure means to draw it accurately. Accurately construction depends on using measuring instruments properly.

Generally, to carry out a construction, you require a sharp pencil, compasses, protractor and a good ruler, set-square and dividers are also necessary.

When making constructions, the following guidelines should be followed.

(1)          A short pencil of about 6cm should be fixed on the 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 construction.

(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.

GENERAL EVALUATION

1. use ruler and set square  to construct a pair of parallel lines that are 5cm apart
2. Draw accurately a line through D parallel to BC in this diagram using ruler and set square.

READING ASSIGNMENT

1.            New general mathematics for JSS 1 by JB Channon and others pages 151

2.            Essential mathematics for JSS 1  by AJS Oluwasanmi

WEEKEND ASSIGNMENT

1.            In construction, __________ is an instrument for drawing lines and measurement of length. (a) compass (b) dividers (c) ruler (d) protractor

2.            The angles between two lines that are perpendicular is (a) 70⁰ (b) 90⁰ (c) 80⁰ (d) 100⁰

3.            In construction __________ is an instrument for constructing  and measuring angles (a) set square (b) compass (c) protractor (d) ruler

4.            These instruments are necessary for construction except _________ (a) compass (b) ruler (c) block (d) protractor

5.            In construction you must be __________ (a) careful (b) careless (c) untidy (d) unprepared

THEORY

1.            In construction, name five basic instruments that are very important

2.            Use ruler and set square construct a rectangle of length 6cm by 3cm.