Topic: Circle Theorems; Geometrical Proof (Higher - Unit 3)
Specification References: G1.1
G1.1 Recall and use properties of angles at a point, angles at a point on a straight line (including right angles), perpendicular lines and opposite angles at a vertex.
Candidates should be able to:
work out the size of missing angles at a point
work out the size of missing angles at a point on a straight line
know that vertically opposite angles are equal
distinguish between acute, obtuse, reflex and right angles
name angles
estimate the size of an angle in degrees
justify an answer with explanations such as ‘angles on a straight line’, etc.
use one lower case letter or three upper case letters to represent an angle, for example x or ABC
understand that two lines that are perpendicular are at 90o to each other
draw a perpendicular line in a diagram
identify lines that are perpendicular
use geometrical language
use letters to identify points, lines and angles
Examples
Three angles form a straight line. Two of the angles are equal. One of the angles is 30° more than another angle. Work out two possible values for the smallest angle.