In a triangle ABC, D is the midpoint of BC. Join AD. Angle ADB = 45 degree and angle ACB = 30 degree. Find angle ABC.
(In reply to
re(2): Solution - This is how long it took me: by Eric)
I worked the the problem on Geometer's Sketchpad.
Since the measured angle was 105 degrees exactly
and it easily satisfies the equation
2 cos(15) 1
----------- = ------------
sin(?) sin(135-?)
I didn't think to write out the derivation.
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Posted by Bractals
on 2006-02-25 18:20:55 |
re(3): Solution - This is how long it took me:
