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mathematicsprinted 70 · PDF 71
165 pagesrevision 46935
printed 70 · PDF 71
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70
Necessary terms, concepts and formulas
Angles: Appearing in most IGCSE Geometry based questions, angles are formed when two
straight lines intersect each other at a point and the corresponding angular distance between
those two lines is called an ‘angle’. Some of the rules relating to angles are shown below.
Angles on a straight line always add up to 180°
Angles at point always add up to 360°
Vertically opposite angles are always equal to each other
The sum of all angles of any triangle add up to 180°
Side Note:
An Isosceles triangle has 2 equal sides and 2 equal angles
An Equilateral triangle has 3 equal sides and 3 equal angles
A Scalene triangle has 0 equal sides and 0 equal angles
A Right-Angled triangle has one angle which is 90° (it will be talked in more detail in later
pages)