Teacher's Guide - Pearson

6. If the second block of wood is half the size, the cost of the second block will beP320 3 (​1__4 ​) = P80.00. He will need 1.2 litres 3 (​ 1__ ​) 5 0.15 litres of varnish.8Extension Activity 13.1 (Student’s Book page 236)1. a) s 5 ​√ ________12 2 1 6 2 ​ 5 13.4 cmb) SA 5 2r 2 1 rs5 2 3 6 2 1 3 6 3 13.416407…5 479.1 cm 22. SA 5 ​9__ ​ 3 479.08800… 5 1 077.9 cm24Project (Student’s Book page 237)Diameter in metres Height in metres Volume in m 31 2.5 1.963751 3 2.35651.5 2.5 4.41843751.5 3 5.3021252 1.75 5.49852 2 6.2841. 1.5 m in diameter and height 3 m is enough.2. The tank with the smallest surface area is the one 1 metre in diameter andheight 2.5 m.3. SA 5 3.142 3 1 3 (0.5 1 2.5) 5 9.426 m 2 .The amount of metal to the nearest metre will be 10 m 2 .Cost: 10 m 2 3 180 + ____ ​ 18 ​ 3 1 800 = P2 124100Revision Exercise (Student’s Book page 238)1. a) 9:4; 27:8b) 2; 82. a) V 5 162 cm 3 ; SA 5 198 cm 2b) 1:4; 1:2c) V 5 20.25 cm 3 ; SA 5 49.5 cm 23. a) SA per ball 5 4r 2 5 254.5 cm 2Leather required 5 3 053.63 cm 2b) Leather required 5 (​2__3 ​)2 3 3053.6351 357.17 cm 24. a) 1:25b) 1:5c) 9 cm76 EXPLORING MATHEMATICS FORM 3