Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Bisect a line segment.
• Bisect a given angle.
• Draw a line parallel to another line.
• Divide a line into equal parts.
• Construct a perpendicular line.

Lesson summary

Engineering Graphics and Design (EGD) provides a crucial foundation for various technical fields, from architecture and engineering to manufacturing and design. In South Africa, where infrastructure development is a national priority, a solid understanding of EGD principles, especially basic geometrical constructions, is invaluable. Whether designing affordable housing, planning transport networks, or developing sustainable energy solutions, the ability to accurately represent and manipulate geometrical shapes is essential.

Lesson notes

Basic geometrical constructions are the foundation of accurate drawing and design. They rely on using only a compass and a straightedge (ruler) to create accurate geometric figures. Here's a detailed explanation of each construction: Bisecting a Line Segment: This means dividing a line segment into two equal parts.

Why it's important: Essential for finding the midpoint of a line, which is crucial in many constructions (e.g., finding the center of a circle or determining the location of support beams).

How to do it: Open the compass to a radius more than half the length of the line segment. Place the compass point on one endpoint of the line segment and draw an arc above and below the line. Without changing the compass radius, place the compass point on the other endpoint and draw arcs that intersect the first two arcs. Draw a straight line through the two points where the arcs intersect. This line bisects the original line segment at its midpoint.