Question

Oblicz pole i obwód trójkąta ABC, wiedziac, że AC = BC = 12cm i miara kąta ACB = 120°

Prosze o pomoc ;)

Answer 1

             C                            skoro ∢ ACB=120°to ∢ACD=60°a ∢CAD 30°

                                          |DC|                 1                    1

                                          ------ = sin30°= ---    =>    DC= ---AC=6            

                                          |AC|                 2                    2

 A         D          B

                                          |AD|                √3                 √3

P=1/2*a*h                           ------= cos 30°= ---   =>    AD= ---AC=6√3

                                          |AC|                 2                   2

AD=6√3 to AB=12√3

P=1/2*12√3*6=36√3

Obw=12√3+12+12=12√3+24