Teacher's Guide - Pearson

12c h a p t e rArea and perimeterSyllabus: General objectiveThis chapter deals with the application of ratio and enlargement/reduction on areaand perimeter.Specific objectives• y Solve problems involving practical applications of ratio on area and perimeter oftwo-dimensional shapes.• y Solve problems involving practical applications of scale factors of enlargement/reduction on area and perimeter of two-dimensional shapes.In this chapter students will learn the skill to manipulate two-dimensional shapeswith regard to their area and perimeter by changing their dimensions by a certainratio or scale factor. It is important that students have a clear understanding ofthe effect that a change to dimensions of a shape has on the area and perimeterof the object.AnswersSupport Activity 12.1 (Student’s Book page 209)Area 1 () 5 l 3 b 5 14 3 6 5 84 cm²Area 2 () 5 ​1__2 ​b 3 h 5 ​ 1__ ​ 3 4 3 6 5 12 cm²2Area 3 ( ) 5 ​1__2 ​πr²5 ​1__2 ​ 3 π 3 165 25.13274122 cm²Total Area 5 84 1 12 1 25.13 5 121.13 cm²Perimeter 5 18 1 6 1 6 1 ​√ _______4 2 1 6 2 ​ 1 1__2 (2π.4)5 32 1 ​√ ___52 ​+ 4π5 32 1 7.21 + 12.575 51.78 cm64EXPLORING MATHEMATICS FORM 3