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Math Help - Angle Help Please

  1. #1
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    Question Angle Help Please

    Find a in the diagram below, giving all reasons.

    Could someone please help me with this question. I have no idea where to start!

    Thanks.
    Attached Thumbnails Attached Thumbnails Angle Help Please-7b-11d.jpg  
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  2. #2
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    Hello, stellina_91!

    I assume that EFHD is a straight line.


    In \Delta CFD\!:\;\angle EFI is an exterior angle.
    . . Hence: . \angle EFI \:=\:\angle C + \angle D \:=\:20^o + 35^o \quad\Rightarrow\quad \angle EFI\:=\:55^o

    In \Delta AIB\!:\;\angle EIF is an exterior angle.
    . . Hence: . \angle EIF \:=\:\angle A + \angle B \:=\:45^o + 30^o\quad\Rightarrow\quad\angle EIF = 75^o

    In \Delta IEF\!:\;a \:=\:\angle IEF \:=\:180^o - 55^o - 75^o \quad\Rightarrow\quad\boxed{ a\;=\;50^o}

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  3. #3
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    Quote Originally Posted by stellina_91 View Post
    Find a in the diagram below, giving all reasons.

    Could someone please help me with this question. I have no idea where to start!

    Thanks.
    The first thing is to realize that in each triangle shown all the angles will add up to 180 degrees. Start there and remember the adjacent opposite angles are equal
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