In the diagram, three points A, B and C are on the same horizontal ground. B is 15m from A, on a bearing of 053°, C is 18m from B on a bearing of 161°. A vertical pole with top T is erected at B such that < ATB = 58°. Calculate, correct to three significant figures, (a) the length of AC. (b) the bearing of C from A ; (c) the height of the pole BT.
Explanation
< PAB = < ABE = 53° (alternate angles) < CBE = 180° - < DBC = 180° - 161° = 19° < ABC = < ABE + < CBE = 53° + 19° = 72° (a) In , = = (b) The bearing of C from A = 61.13° + 53° = 114.13° 114°. (c) In ,
