Problem

Source:

Tags: Iran, geometry



Find the angles of triangle $ABC$. [asy][asy] import graph; size(9.115122858763474cm); real labelscalefactor = 0.5; /* changes label-to-point distance */ pen dps = linewidth(0.7) + fontsize(10); defaultpen(dps); /* default pen style */ pen dotstyle = black; /* point style */ real xmin = -7.9216637359954705, xmax = 10.308581981531479, ymin = -6.062398124651168, ymax = 9.377503860601273; /* image dimensions */ /* draw figures */ draw((1.1862495478417192,2.0592342833377844)--(3.0842,-3.6348), linewidth(1.6)); draw((2.412546402365528,-0.6953452852662508)--(1.8579031454761883,-0.8802204313959623), linewidth(1.6)); draw((-3.696094000229639,5.5502174997511595)--(1.1862495478417192,2.0592342833377844), linewidth(1.6)); draw((-1.0848977580797177,4.042515022414228)--(-1.4249466943082025,3.5669367606747184), linewidth(1.6)); draw((1.1862495478417192,2.0592342833377844)--(9.086047353374928,-3.589295214974483), linewidth(1.6)); draw((9.086047353374928,-3.589295214974483)--(3.0842,-3.6348), linewidth(1.6)); draw((6.087339936804166,-3.904360930324946)--(6.082907416570757,-3.319734284649538), linewidth(1.6)); draw((3.0842,-3.6348)--(-2.9176473533749285,-3.6803047850255166), linewidth(1.6)); draw((0.08549258342923806,-3.9498657153504615)--(0.08106006319583221,-3.3652390696750536), linewidth(1.6)); draw((-2.9176473533749285,-3.6803047850255166)--(-6.62699301304923,-3.7084282888220432), linewidth(1.6)); draw((-6.62699301304923,-3.7084282888220432)--(-4.815597805533209,2.0137294983122676), linewidth(1.6)); draw((-5.999986761815922,-0.759127399441624)--(-5.442604056766517,-0.9355713910681529), linewidth(1.6)); draw((-4.815597805533209,2.0137294983122676)--(-3.696094000229639,5.5502174997511595), linewidth(1.6)); draw((-4.815597805533209,2.0137294983122676)--(1.1862495478417192,2.0592342833377844), linewidth(1.6)); draw((-1.8168903889624484,2.3287952136627297)--(-1.8124578687290425,1.744168567987322), linewidth(1.6)); draw((-4.815597805533209,2.0137294983122676)--(-2.9176473533749285,-3.6803047850255166), linewidth(1.6)); draw((-3.5893009510093994,-0.7408500702917692)--(-4.1439442078987385,-0.9257252164214806), linewidth(1.6)); label("$A$",(-4.440377746205339,7.118654172569505),SE*labelscalefactor,fontsize(14)); label("$B$",(-7.868514331571194,-3.218904987952353),SE*labelscalefactor,fontsize(14)); label("$C$",(9.165869786409527,-3.0594567746795223),SE*labelscalefactor,fontsize(14)); /* dots and labels */ dot((3.0842,-3.6348),linewidth(3.pt) + dotstyle); dot((9.086047353374928,-3.589295214974483),linewidth(3.pt) + dotstyle); dot((1.1862495478417192,2.0592342833377844),linewidth(3.pt) + dotstyle); dot((-2.9176473533749285,-3.6803047850255166),linewidth(3.pt) + dotstyle); dot((-4.815597805533209,2.0137294983122676),linewidth(3.pt) + dotstyle); dot((-6.62699301304923,-3.7084282888220432),linewidth(3.pt) + dotstyle); dot((-3.696094000229639,5.5502174997511595),linewidth(3.pt) + dotstyle); clip((xmin,ymin)--(xmin,ymax)--(xmax,ymax)--(xmax,ymin)--cycle); /* end of picture */ [/asy][/asy] Proposed by Morteza Saghafian