6A 1

2A 1. F=108 4. E=196 7. a=306 10. M=80.5

2. d=30 5. D=40 8. W=105 11. e=0.006

3. C=31.42 6. V=82.5 9. T=17 12. V=312.01

2B 1(a) w=4 (b) w=4·167 (c) w=4·3 (d) w=3·5 (e) w=5

2(a) l=11 (b) l=8·3 (c) l=8·125 (d) l=6·5 (e) l=7·07

2C 1. l=6.25 5. d=39.79 9. g=6 13. r=17

2. a=7.5 6. l=7.5 10. F=12.5 14. g=9.8

3. b=8 7. a=24 11. m=9.80 15. y=30

4. s=4.29 8. p=103.33 12. m=22

Return to Using Formulae

6A 1. 78.54cm² 2. 254.47cm² 3. 15393.80cm²

Return to Order of Operations

8A 1. P=2(l+w) 2. P=2(l+w) 3. P=2(l+w) 4. P=2(l+w)

30=2(l+7) 66=2(l+14) 48=2(18+w) 53=2(17+w)

15=l+7 33=l+14 24=18+w 26·5=17+w

8=l 19=l 6=w 9·5=w

5. 2x+54 = 180 6. 2x+28 = 180

2x = 126 2x = 152

x = 63 x = 76

7. 2x+y = 180 8. 2x+y = 180

2x28+y = 126 2x71+y = 152

y = 180 - 56 y = 180 – 142

y = 124 y = 38

18B 1. AB=7.88cm 3. AB=6.02cm 5. AB=5.27cm

2. AB=6.51cm 4. AB=4.91cm 6. AB=8.82cm

The pages in this section are from the book WHY ALGEBRA? (Second Edition, 2005)

For more details please e-mail whyal@y-maths.co.uk