Posted by Tom on Sunday, October 14, 2012 at 12:23pm.
ÚABC ~= ÚACB
BD perpendicular AC
The sum fo the three angles in any triangle is 180 degree.
Prove: mÚCBD = 1/2 mÚBAC

Math  Tom, Sunday, October 14, 2012 at 12:33pm
angle ABC ~= angle ACB
BD perpendicular AC
The sum fo the three angles in any triangle is 180 degree.
Prove: mangle CBD = 1/2 mangle BAC 
Math  Reiny, Sunday, October 14, 2012 at 12:51pm
let angle CBD = a
in trianagle ABC:
2x + y = 180
in triangle BCD
a + x = 90 or 2a + 2x = 180
then 2a + 2x = 2x + y , both equal to 180
2a = y
a = (1/2y
or
angle CBD = (1/2) angle BAC