Cambridge International Mathematics

Example 2 Self Tutor

Solve forx:

ab

a Obtuse AOBb = 360o¡ 250 o

fangles at a pointg

) AOBb = 110o

) 2 x= 110 fangle at the centreg

) x=55

b BbDC=AbBD falternate anglesg

AbBD=AbCD fangles on same arcg

) BbDC=AbCD

) x=36

EXERCISE 27A.2

1 Find, giving reasons, the value ofxin each of the following:

abc

de f

2 Find, giving reasons, the values of the unknowns in the following:

abc

de f

250°

x°

A B

C

O

AB

D C

x° 36°

x°

128 °

O

x°

80 °

O

x°

45 °

x° 100 °

O

x°

88 °

33 ° x° 50 ° O

O

x°^46 °

x°

y°

30 °^40 °

a°

b°

50 °

c°

70 °a°

55 °

x° y°

75 °

43 °

a°

b°

80 °

O

O

554 Circle geometry (Chapter 27)

IGCSE01

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Y:\HAESE\IGCSE01\IG01_27\554IGCSE01_27.CDR Monday, 27 October 2008 2:40:38 PM PETER