1. Targeting Grade C Angles SSM1 GCSE Mathematics

2. Practice 1:: To recognise vertically opposite, alternate (Z), corresponding (F) and interior angles Practice 2: To remember that angles in a triangle add up to 180º Question 1 Practice 3: To remember that the angles in a quadrilateral add up to 360º Practice 4:To work out sum of the interior angles of your polygon. A formula will help Questions 2 Can you: Use angle facts to calculate angles: Associated with parallel lines In a triangle Try some questions In a quadrilateral In any polygon Try some questions If not you need

3. Angles associated with parallel lines

4. Click to begin

20. These are all parallel lines.

21. Click to continue

29. What is the connection between the yellow angles? Click to continue

30. They are equal because the are in corresponding positions. They are called corresponding angles Click to continue

46. Notice that even though the size of the angles change, they are still equal. Click to continue

47. They are equal because the are in corresponding positions. They are called corresponding angles Click to continue

51. These are vertically opposite angles. Click to continue

52. What do you think the relationship is between them?

57. These angles are called alternate angles. They are equal. Click to continue

62. What are the yellow angles called? Click to continue

63. What are the blue angles called? Click to continue

65. What is the link between the size of the yellow angles and the blue angles? Click to continue

73. These angles are called interior angles.They are inside the parallel lines. Click to continue

74. These are also interior angles. Click to continue

75. What do you think is the relationship between these? Click to continue

80. 136º x Find the missing angle marked x

81. 95º x Find the missing angle marked x

82. 125º x Find the missing angle marked x

83. 105º x z y Find the sizes of the angles marked with letters 95º a c b Click for answers X = 75º Y = 105º Z = 105º a = 85º b = 85º c = 85º Which angle do you need to work out first?

84. 124º x y Find the missing angles marked x and y

85. 118º x Find the missing angle marked x Go back to objectives

86. Angles in a triangle

87. What are the yellow angles called? What are the red angles called? Click to continue

97. Notice the red, yellow and green angles. Click to continue

98. They are inside the purple triangle.

99. and on a straight line.

100. So the number of degrees in a Triangle must be the same as in a straight line. Click to continue

101. Which is?

102. a 60º 45º Find angle a

103. b 37º 48º Find angle b

104. c 40º c Find the angles marked c

105. 3x x 2x Back to objectives What is the size of each of the angles?

106. Questions 1 Questions to practice angles associated with parallel lines and in triangles

107. SSM 1 Conundrum - Calculating angles 1 You can use what you know about angles to calculate angle  and angle . There is more than one way to calculate these angles. How many different ways are there? Explain. Are there any other angles here that you could calculate? Explain

108. Calculating angles 2 Explain how you would calculate angle  and angle  The line AD looks as though it could be equal to the line CD. Is it? How do you know? Back to objectives

109. Angles in a quadrilateral

110. Every quadrilateral can be divided into two triangles each containing 180º 2 x 180 = 360º 1 2 1 2 1 2 1 2

111. 70º x y Find the missing angles

112. 75º x y Find the missing angles

113. x 60º 55º x = º 145º

114. x 100º 55º x = º 95º

115. x 200º 25º x = º 115º

116. x x x = º 2x Back to objectives

117. Angles in a polygon Formula to use to calculate the sum of the interior angles in a polygon (n – 2) x 180 = total number of degrees n is the number of sides in the polygon

118. If you forget this formula you can always divide the shape into triangles Can be divided into three triangles Each triangle has an angle sum of 180º So, angle sum of the pentagon is 3 x 180 = 540º 1 2 3

119. How many sides does the shape have? Apply the formula (n-2) x 180 to find the sum of the interior angles If this is a regular hexagon, calculate the size of each of the interior angles Click for answers 6 (6 – 2) x 180 = 4 x 180 = 720º 720 ÷ 6 = 120º

120. x 70º x = º 140º 130º

121. x 110º 100º x = º 110º 120º

122. x 140º x = º 140º 80º Back to objectives

123. Questions 2 Practice questions using angles associated with quadrilaterals and polygons

125. Back to objectives