In the previous lesson we dealt with the theorem that says ... - AdMaths
In the previous lesson we dealt with the theorem that says ... - AdMaths
In the previous lesson we dealt with the theorem that says ... - AdMaths
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GR. 12 DERDE VRAESTEL : MEETKUNDE<br />
LES 3 : SIRKELMEETKUNDE :<br />
DIE OMTREKSHOEK IN ‘N SEMI-SIRKEL EN<br />
MOEILIKER VOORBEELDE OOR MIDDELPUNTSHOEKE EN OMTREKSHOEKE<br />
3.2 VOORBEELDE<br />
A<br />
Bls. 2 van 5<br />
1. Bereken die onbekende hoeke. O is die middelpunt van die sirkel. Gee redes.<br />
Oplossing<br />
D<br />
20°<br />
z = 180° – 60° ( reguitlyn )<br />
z = 120°<br />
60°<br />
z<br />
O<br />
C<br />
x<br />
y<br />
x = 60° ( midpts. = 2 omtreks op koord DA )<br />
Sien jy dat z die middelpuntshoek op DA en dat x die omtrekshoek op DA is?<br />
ABC = 90° ( omtreks in ‘n semi-sirkel )<br />
Dus is y = 180° – 20° – 90° ( som of e van Δ = 180° )<br />
y = 70°<br />
B
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