Teacher's Guide - Pearson

5. a) Angle ADE = 80º (Corresponding angles)b) Angle FEC = 40º (Corresponding angles)c) EF = 5 cm. D is the midpoint because E is the midpoint of AC and ED isparallel to BC. Hence DB = EF because of a parallelogram.Extension Activity 6.2 (Student’s Book page 106)Scale factor of length in the triangles is half. Therefore the scale factor of the areas isone quarter.∴ Area BAC 5 20 cm 2∴ Area BKMC 5 20 cm 2 2 5 cm 2 5 15 cm 2Activity 6.2 (Student’s Book page 106)SSS: EnoughAAA: Not enoughSAS: EnoughSSA: Not enoughSAA: EnoughRSH: EnoughSupport Activity 6.3 (Student’s Book page 108)1. a) FJ 5 7.5 cmb) QJ 5 5.2 cmc) RQ 5 6.8 cm2. FJQ3. The formed alternating angles are equal.Exercise 6.3 (Student’s Book page 109)1. PQM and PSM (RSH)PQR and PSR (SSS)QMR and SMR (RSH)2. MO 5 10 cm, N 5 60°3. a) XOY and WOZ are congruent.b) They are congruent because of the SAS rule.c) XY 5 WZ because XOY WOZ.38 EXPLORING MATHEMATICS FORM 3