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Need help with the statements and proofs pls help I’m in need

Need help with the statements and proofs pls help I’m in need-example-1
User Mithlesh Kumar
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2 Answers

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27 votes

Explanation:

AB is a straight line. all angles around one point (here O) on one side of the line are 180°. after all, a line can be seen as the diameter of a circle, one side deals with a half-circle and therefore 180° (half of 360° of a full circle).

so, AOC and COB are supplementary angles (together they have 180°).

AOC + COB = 180° | dividing both sides by 2

AOC/2 + COB/2 = 180/2 = 90°

AOD = DOC = AOC/2

COE = EOB = COB/2

we can therefore put any of these bisected angles in place of the half main angles in the main equation :

DOC + COE = 90°

therefore, OD and OE enclose a right angle (90°).

User Alastair Irvine
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12 votes
12 votes

Answer:

See below for proof.

Explanation:


\textsf{If $\overrightarrow{OD}$ bisects $\angle AOC$ then}:


\angle AOD=\angle DOC


\textsf{If $\overrightarrow{OE}$ bisects $\angle COB$ then}:


\angle COE=\angle EOB


\textsf{Angles on a straight line sum to $180^(\circ)$}:


\implies \angle AOD + \angle DOC + \angle COE + \angle EOB = 180^(\circ)


\implies 2 \angle DOC + 2\angle COE = 180^(\circ)


\implies 2 \left(\angle DOC + \angle COE\right) = 180^(\circ)


\implies \angle DOC + \angle COE = 90^(\circ)


\textsf{Perpendicular lines are lines that are at $90^(\circ)$ to each other}.


\textsf{Therefore, $\overrightarrow{OD} \perp \overrightarrow{OE}$}.

User Praveen Matanam
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