Module 1.3 Geometry, graphs and trigonometry

Knowledge levels

Item	A	B1	B2 / B2L	B3
1.3(a) Simple geometrical constructions	—	1	1	1
1.3(b) Graphical representation: nature and uses of graphs, graphs of equations/functions	2	2	2	2
1.3(c) Simple trigonometry: trigonometrical relationships, use of tables, rectangular and polar coordinates	—	2	2	2

Category A is examined only on graphs at this sub-module.

Angles and shapes

• Full circle = 360° = 2π radians; 1 rad ≈ 57.3°. Right angle = 90°, straight line = 180°.
• Acute below 90°, obtuse 90-180°, reflex above 180°. Complementary angles add to 90°, supplementary to 180°.
• Angles in a triangle add to 180°; in a quadrilateral to 360°. Interior angles of an n-sided polygon = (n − 2) × 180°.
• Triangles: equilateral (3 equal sides, 60° each), isosceles (2 equal sides and angles), scalene (none equal), right-angled.
• Circle terms: radius, diameter, chord, arc, sector, segment, tangent (meets the radius at 90°).

Simple constructions

Typical constructions with compass and straight edge: bisecting a line (perpendicular bisector), bisecting an angle, drawing a perpendicular from a point, constructing 60° (equilateral triangle) and 90°, finding the centre of a circle (intersection of the perpendicular bisectors of two chords). The centre-finding method is used in the workshop to locate the centre of a round bar.