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

  • Thread starter Thread starter anemone
  • Start date Start date
  • Tags Tags
    Altitude Triangle
Click For Summary
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.
anemone
Gold Member
MHB
POTW Director
Messages
3,851
Reaction score
115
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 $\angle QCA$.
 
Mathematics news on Phys.org
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!
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 21 ·
Replies
21
Views
5K