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(b) The direction of Q from O is S 40 0 E (start from South, turn 40 0 towards the East) Directions should always be measured eastwards or westwards from the north or from the south; never from the east or west. (c) The direction of R from O is N 25 0 W (start from North turn 25 0 towards the west). (c) The direction of T from O is South 70 0 west. N R 25 0 N O T 20 0 O Example Consider points P, Q and R in the following figure. N Q 140 0 P The bearing of each point from one another can be found by measuring the angles. The mark is inserted to assist in identifying the bearing or the required angle. The bearing of R from Q is 140 0 . The bearing of P from Q is 230 0 . The bearing of Q from P is 050 0 . The bearing of Q from R is 320 0 . Example Village A and B are such that the bearing of B from A is 075 0 . The distance between A and B is 15 km. (a) Represent the above information in a scale drawing. (b) Calculate the bearing of A from B. Solution 50 0 (a) First we draw a sketch. R
N A B 15km S 75 0 A Then we choose a suitable scale to draw an accurate scale drawing. Use the scale of 1 cm represents 3 km. The accurate scale drawing is shown below. N A B 75 0 5cm x S A (a) To calculate the bearing of A from B, consider line AB as a transversal of two parallel lines passing through A and B respectively. The bearing of A from B is greater than 180 0 . The angle indicated as x is alternate to the angle marked at A, which is 75 0 . Therefore x = 75 0 . Therefore the bearing of A from B is 180 0 + 75 0 = 255 0 . Example Village P is 25 km due east of village Q. Village R is 20 km from Q on a bearing of S 45 0 W. (a) Find the distance between R and P. (b) Find the bearing of R from P. Solution We draw a sketch first. N A N A Q N 45 0 25km P B R S S A We use a scale of 1 cm represents 5 km in making an accurate scale drawing.
Page 1 and 2: APPROXIMATIONS Rounding off Example
Page 3 and 4: Significant figures (sf) Significan
Page 5 and 6: Exercise 1. A man in Nairobi receiv
Page 7 and 8: 3. A radio that cost sh. 15 000 was
Page 9 and 10: 1 20000 ×1 2 × 21 Therefore, = sh
Page 11 and 12: 8. A business man had sh. 1 200 000
Page 13 and 14: 2. A dealer marks a price sh. 4 800
Page 15 and 16: (ii) income tax (sh.) 10 100 000 10
Page 17 and 18: (b) Express the total income tax fo
Page 19 and 20: O is at the vertex of the angle, an
Page 21 and 22: Exercise 1. In the figure shown, x
Page 23 and 24: t s 75 0 Solution s and 75 0 are ve
Page 25 and 26: The measurements of the scale drawi
Page 27 and 28: 5. The floor of a school hall is re
Page 29: (i) Compass bearings On a compass,
Page 33 and 34: - We measure AB = 4.8cm. But 1cm re
Page 35 and 36: Types of polygons Name Number of si
Page 37 and 38: 50 0 +w +x = 180 0 50 0 + 50 0 + x
Page 39 and 40: (d) (e) Quadrilaterals These are fl
Page 41 and 42: n n-2 From the above table we see t
Page 43: 8. One of the large and one of the

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