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- Dec 12th 2008, 11:27 AMdgenerationx2circle questions 3
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- Dec 12th 2008, 11:52 AMmasters

Hello dgen,

(20) $\displaystyle m\angle AOB=70$

The angle adjacent to $\displaystyle \angle AOB$ is $\displaystyle \angle COB$.

$\displaystyle m\angle COB=110^{\circ}$ because these two angles make up a linear pair and are supplementary.

$\displaystyle \angle COB$ is a central angle and has the same measure as its intercepted arc.

Therefore, $\displaystyle m\widehat{CB}=110^{\circ}$

(24) The measure of an inscribed angle in a circle is one-half the measure of its intercepted arc.

$\displaystyle 3x+7=\frac{1}{2}(134)$

$\displaystyle 3x+7=67$

$\displaystyle 3x=60$

$\displaystyle x=20$

(26) $\displaystyle m\widehat{XY}=40^{\circ}$

$\displaystyle m\widehat{WX}=180-40=140^{\circ}$