©G Dear2008 – Not to be sold/Free to use Stage 5 Years 9 & 10 Compass & True Bearings Bearings Press Ctrl-A ©G Dear2008 – Not to be sold/Free to use

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

Bearing Ex 1 (2/4) A. .L .B Ship A is 17km west of a lighthouse L. N Ship B is due south of the lighthouse L. Ship B is SE of ship A. Calculate distance d from Ship A to ship B. A. 17 km .L 45o 17 d Cos 45o = d d = 17 ÷ Cos 45o .B ≈ 24 km 3

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

Find Mary’s bearing from her starting position. Bearing Ex 3 (4/4) Mary walks 3.4 km east , then 1.3 km south. Find Mary’s bearing from her starting position. 90o 3.4 km θo 1.3 3.4 Tan θo = 1.3 km Tan-1 ( ) 1.3 3.4 θo = ≈ 21o Bearing = 90o + 21o = 111o 5