Angle calculations a Angles in a half turn = Angles in a full turn = b Opposite angles are equal c d e Angles in a triangle = j F angles are equal 57 0 hi Z angles are equal 42 0 fg k l Angles in a quadrilateral = Angles in an isosceles triangle m 8080 Use the rules to work out all angles
Angles and polygons e e e c c c c c c ie Interior = e angles Angles at = 360 the centre No. of sides Exterior = 360 angles No. of sides There are 3 types of angles in regular polygons Calculate the value of c, e and i in regular polygons with 8, 9, 10 and 12 sides Answers: 8 sides = 45 0, 45 0, sides = 40 0, 40 0, sides = 36 0, 36 0, sides = 30 0, 30 0, To calculate the total interior angles of an irregular polygon divide it up into triangles from 1 corner. Then no. of x 180 Total i = 5 x 180 = 900 0