![OBMEP - O triângulo ABC é isósceles de Base BC e o ângulo BÂC mede 30°. O triângulo BDC é isósceles. - YouTube OBMEP - O triângulo ABC é isósceles de Base BC e o ângulo BÂC mede 30°. O triângulo BDC é isósceles. - YouTube](https://i.ytimg.com/vi/Fi8QTdBcxBM/maxresdefault.jpg)
OBMEP - O triângulo ABC é isósceles de Base BC e o ângulo BÂC mede 30°. O triângulo BDC é isósceles. - YouTube
![Two triangles ABC and DBC lie on the same side of the base BC. From a point P on BC, PQ||AB and PR||BD are drawn. They meet AC in Q and DC Two triangles ABC and DBC lie on the same side of the base BC. From a point P on BC, PQ||AB and PR||BD are drawn. They meet AC in Q and DC](https://haygot.s3.amazonaws.com/questions/1008405_bf1c3117c0dc43dd8b37627e141604db.png)
Two triangles ABC and DBC lie on the same side of the base BC. From a point P on BC, PQ||AB and PR||BD are drawn. They meet AC in Q and DC
![triangle isocèle et angle à la base / Le coin des beaux problèmes de Géométrie / Forum de mathématiques - Bibm@th.net triangle isocèle et angle à la base / Le coin des beaux problèmes de Géométrie / Forum de mathématiques - Bibm@th.net](https://zupimages.net/up/22/09/6gk3.png)
triangle isocèle et angle à la base / Le coin des beaux problèmes de Géométrie / Forum de mathématiques - Bibm@th.net
![The base BC of an equilateral triangle ABC lies on y - axis . The coordinates of the point C are (0, - 3). If the origin is the mid - point The base BC of an equilateral triangle ABC lies on y - axis . The coordinates of the point C are (0, - 3). If the origin is the mid - point](https://haygot.s3.amazonaws.com/questions/1274727_1367709_ans_faee93dd20b44356ac2dcda115bf8bda.jpg)