9766
/www/nrich/html/content/id/9766/
1
2013-01-04T16:13:48
<?xml version="1.0" encoding="UTF-8"?>
<mdoxml version="1.0"><br></br>
<mdo:image src="weekly.png" style="float: left;"></mdo:image>What is the value of $x$ in this diagram?</mdoxml>
<?xml version="1.0" encoding="UTF-8"?>
<mdoxml version="1.0"><mdo:image src="weeklysol.png" style="float: right;"></mdo:image><br></br>
Alternate angles BDF and DFG are equal, so lines BD and FG are parallel.<br></br>
Therefore angle BCA = angle FGC = $80^{\circ}$ (corresponding angles).<br></br>
<br></br>
Consider triangle ABC: $x + 70 + 80 = 180$ so $x=30$.</mdoxml>
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Weekly Problem 7 - 2013
Weekly Problem 7 - 2013