8. CK = 11
CD = ?

CK = KD = 11
CD = 11 + 11 = 22

10. MF : FN = 4 : 3
MN = 28

4 + 3 = 7
28 : 7 = 4
4* 4 = 16 (MF)
4 * 3 = 12 (FN)

11. AC : CB = 2 : 5
AC = 6
AB = ?

6 : 2 = 3
3 * 5 = 15
6 + 15 = 21 (AB)

12. MN = 19
MF — FN = 9

19 — 9 = 10
10 : 2 = 5 (FN)
5 + 9 = 14 (MF)

18. <ABC = 40^o
<ABD = <DBC = 40/2 = 20^o

19. <ABC = 65^o
<ABD = <DBC = 65/2 = 32,5^o

28. <AOB = 180^o
<AOM = 1/6
<MON = 2/3
<BON = ?

1/5 + 2/3 = 3 + 10 / 15 = 13/15
15/15 — 13/15 = 2/15
180/1 * 2/15 = 24^o (<BON)
180/1 * 1/5 = 36^o (<AOM)
180/1 * 2/3 = 120^o (<MON)

29. <ABC = 77^o
<ABD, <DBC = ?

77 — 17 = 60^o
60 : 2 = 30^o (<DBC)
30 + 17 = 47^o (<ABD)

30. <ABC = 155^o
<ABD, <DBC = ?

155 — 23 = 132^o
132 : 2 = 66^o (<ABD)
66 + 23 = 89^o (<DBC)

31. <ABC = 120^o
<ABD, <DBC = ?

3x + x = 120^o
4x = 120^o
x = 30^o (<DBC)
3x = 30 * 3 = 90^o (<ABD)

32. ABC = 160^o
<ABD, <DBE, <EBC = ?
ABC : DBE : EBC = 1 : 3 : 4

1 + 3 + 4 = 8
160 : 8 = 20^o
1 * 20 = 20^o (<ABD)
3 * 20 = 60^o (<DBE)
4 * 20 = 80^o (<EBC)

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