Basic triangle plane geometry problem - impossible?

Click For Summary
SUMMARY

The problem involves finding angle PAC in triangle ABC, where angle PBC is 10 degrees, angle PCB is 20 degrees, and angle BAC is 100 degrees. The discussion concludes that angle PAC is not uniquely solvable, as point A can lie anywhere on an arc of a circle, allowing PAC to vary between 0° and 100°. This geometric ambiguity highlights the complexities of triangle geometry in relation to inscribed angles.

PREREQUISITES
  • Understanding of triangle geometry and properties of inscribed angles.
  • Familiarity with angle relationships in polygons.
  • Basic knowledge of geometric constructions and loci.
  • Experience with Olympiad-level mathematics problems.
NEXT STEPS
  • Explore the properties of inscribed angles in circles.
  • Study geometric loci and their implications in triangle geometry.
  • Learn about angle chasing techniques in Olympiad mathematics.
  • Investigate the relationship between angles and arcs in circular geometry.
USEFUL FOR

Mathematics students, geometry enthusiasts, and individuals preparing for Olympiad-level competitions will benefit from this discussion.

rieuk
Messages
11
Reaction score
0
Consider a point P inside a triangle ABC. Angle PBC is 10 degrees, angle PCB is 20 degrees, and angle BAC is 100 degrees. Find angle PAC.

Question is that is this problem even solvable? I found it in an Olympiad training book...
 
Physics news on Phys.org
hi rieuk! :smile:

no, A could be anywhere on an arc of a circle, so PAC could be anything between 0° and 100° :confused:
 
That's what I thought! Cheers!
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 30 ·
2
Replies
30
Views
11K
  • · Replies 7 ·
Replies
7
Views
10K
Replies
4
Views
3K