MHB Finding $\angle QCA$ from Altitude $AM$ of Triangle $ABC$

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To find angle QCA in triangle ABC with point Q on altitude AM, given angles QBA at 20 degrees, QBC at 40 degrees, and QCB at 30 degrees, the problem requires applying triangle angle properties. The sum of angles in triangle QBC can be used to determine angle QCA. By calculating the remaining angles, angle QCA is found to be 90 degrees minus the sum of angles QBA and QBC. The solution confirms the relationships between the angles and the properties of the triangle. The discussion emphasizes the importance of understanding triangle geometry to solve for unknown angles.
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If $Q$ is a point on the altitude $AM$ of triangle $ABC$, and that $\angle QBA=20^{\circ}$, $\angle QBC=40^{\circ}$ and $\angle QCB=30^{\circ}$, find $\angle QCA$.
 
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anemone said:
If $Q$ is a point on the altitude $AM$ of triangle $ABC$, and that $\angle QBA=20^{\circ}$, $\angle QBC=40^{\circ}$ and $\angle QCB=30^{\circ}$, find $\angle QCA$.
Point Q must be the orthocenter of
$\triangle ABC $
we have :$\angle QCA+30+40=90$
$\therefore \angle QCA=20^o$
 
Albert said:
Point Q must be the orthocenter of
$\triangle ABC $
we have :$\angle QCA+30+40=90$
$\therefore \angle QCA=20^o$

Well done, Albert! Well done!(Yes) And thanks for participating!
 

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