![](http://perplexus.info/images/perplexus/problem/mta3-puz.gif)
Triangle ABC has side AB=AC, and angle BAC = 20 degrees.
D is a point on side AC with AD=BC. Find angle DBC.
Solve this without trigonometry.
(In reply to
re: first part by Jim)
If you split original angle B in half, an iso triangle has the property such that the perimeter of the new, smaller triangle is the same as one side of the 2 equal sides of the original triangle.
WHY?
If angle A gets larger, CB gets larger, angle B gets smaller and moves the point F down CA, such that the property remains true!
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Posted by Jim
on 2004-09-09 14:58:27 |