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Q21. Construct ZABC = 80°using a protractor and bisect it using a ruler and acompass. Write the measure of the bisected angles. |
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Answer» Answer: 120 Step-by-step explanation: 1. Draw a ray OA. 2. With the help of a protractor , construction ∠ BOA = 80∘ 3. Taking O as center and any suitable RADIUS , draw an arc to intersect RAYS OA and OB at points P and Q respectively . 4. Take radius more than half the radius OP.With this radius MAKE an arc from point P and Q which will intersect at X . By joining O and X we get bisector of ∠AOB . Let ray OC be the bisector of ∠ BOA , then ∠ COA = 21∠ BOA = 21×80∘=40∘ . 5. With Q as center and radius equal to PQ , draw an arc to cut the extended arc PQ at R . Join OR and produce it to form ray OD , then ∠ DOA = 2∠ BOA = 2×80∘=160∘. 6. Bisect ∠ DOB as done in step 4. Let OE be the bisector of ∠ DOB is then ∠ EOA = ∠ EOB + ∠ BOA = 21∠ DOB + ∠ BOA = 21(80)∘+80∘=40∘+80∘=120∘ |
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