1 Press Ctrl-A ©G Dear2008 – Not to be sold/Free to use Bearings Stage 6 - Year 12 General Mathematic (HSC)

2 Bearing (1/4) Bearings are used to describe direction. Compass bearings have four main directions and four middle directions NE SESW NW E N S W True Bearings are more specific, using a 3-digit angle clockwise from North. Web Practice 1Practice 2 Web Practice 3

33 Bearing Ex 1 (2/4) A Ship A is 17km west of a lighthouse L. A.A.A.A..B.B.B.B.L.L.L.L B Ship B is due south of the lighthouse L. BSE Ship B is SE of ship A. 45 o N 17 km A Calculate distance d from Ship A to ship B. d Cos 45 o = 17 d d = 17 ÷ Cos 45 o ≈ 24 km

44 Bearing Ex 2 (3/4) sails for 20 km on a bearing of 130 o. A Ship sails for 20 km on a bearing of 130 o. 130 o ? How far south is the ship from its starting point? 20 km d 50 o Cos 50 o = d 20 d = 20 x Cos 50 o ≈ 12.9 km

55 Bearing Ex 3 (4/4) Mary walks 3.4 km east, then 1.3 km south. 3.4 km 1.3 km θoθoθoθo Find Mary’s bearing from her starting position. Tan θ o = θo =θo = Tan -1 ( ) o ≈ 21 o Bearing = 90 o + 21 o = 111 o