This one is compliments of my brother, who got it from some IQ test. I haven't
had time to work on it yet.
There is a triangle ABC, AB = AC. The angle ABC = ACB = 80
degrees. Draw a straight line from point B to side AC that intersects
AC at point D, such that the angle ABD = 20 degrees. Draw another
straight line from point C to side AB that intersects AB at point E,
such that the angle ACE = 10 degrees. Find the angle DEC.
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