Question 1106180
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Since AB/BD = 3/4, let AB=3x and BD=4x.
We know BD = 66, so
{{{4x=66}}}; {{{x=16.5}}}; {{{AB = 3x = 49.5}}}
And then we know {{{AD = AB+BD = 66+49.5 = 115.5}}}<br>
Since AC/CD = 5/6, let AC=5y and CD=6y.  Then since AC+CD = AD,
{{{5y+6y=115.5}}}; {{{11y = 115.5}}}; {{{y = 10.5}}}
And then we know {{{AC = 5y = 52.5}}}<br>
The length of AC is 52.5.