Angle Properties and Circle Theorem

IGCSEMATHSGEOMETRY




Angle Properties and Circle Theorems
Line, Ray, Line Segment (Review):

Line: It does not have a definite length or an end point and can be extended in both directions. It is
represented by the symbol. Line AB is written as AB . It cannot be measured.

Ray : It…

IGCSEMATHSGEOMETRY




Since the angles of a triangle add up to 180°, the sum of the interior angles of a polygon will be 180(n-2)
degrees.

Example: The trapezium has 4 sides.

180(4-2)= 180(2)=360°


The Sum of exterior angles of a polygon:


a b Angles a, b, c, d, e are the…

IGCSEMATHSGEOMETRY




Angle between Tangent and Radius:




The angle between tangent of a point and the radius to the same point
on the circle forms a right angle (which is 90°)

Angle properties of Irregular polygons:

To find the angle of an irregular polygon, you have to keep in mind that…

IGCSEMATHSGEOMETRY




If the angle at the center is 2x, then each of the angles at the circumference must be equal to x°

Angles in opposite segments:

A




B




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