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I need help with this I also need to show my work in order to get credit

I need help with this I also need to show my work in order to get credit-example-1
User Madsobel
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1 Answer

13 votes
13 votes

We want to find the measure of arc AD. We would need to find x first as this would guide us toward finding AD.

We know from a circle geometry theorem that;

I. Angles in the same segment are equal. In this case,


\angle ABD\approx\angle ACD

Therefore, we can equate them, equating them we obtain;


\begin{gathered} 11x-3=8x+15 \\ 11x-8x=15+3 \\ 3x=18 \\ x=6 \end{gathered}

We could use this to obtain the measures of angle ABD or ACD, obtaining one is enough as they are congruent, let us use
\begin{gathered} \angle ABD=11x-3 \\ =11(6)-3_{} \\ =66-3 \\ =63^o \end{gathered}We can therefore find the measure of angle AD, by using the circle geometry theorem;

ii. Angles subtended at the centre of a circle is twice that subtended at the circumference;

Thus;


\begin{gathered} \angle AED=2\angle ACD \\ \angle AED=2(63) \\ \angle AED=126^o \end{gathered}

Therefore, the measure of arc AD is 126 degrees.

User AlexeyGorovoy
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