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Which angle in the figure below measures 90 degrees? Explain how you know

Which angle in the figure below measures 90 degrees? Explain how you know-example-1
User Michael Ninh
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1 Answer

22 votes
22 votes

Given that


\angle\text{BKD}=70^o\text{ and }\angle\text{DKC}=20^o

We know that


\angle BKC=\angle BKD+\angle DKC


\text{ Substitute }\angle\text{BKD}=70^o\text{ and }\angle\text{DKC}=20^o,\text{ we get}


\angle BKC=70^o+20^o

Adding 70 and 20, we get


\angle BKC=90^o

Hence the angle BKC is 90 degrees.

User Joseph Redfern
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