Notam Ab=a,AO=b si BO=c, x=<BAO.
Au loc relatiile;
[tex]b^2+c^2=a^2,a+c=2b,sinx= \frac{c}{a} [/tex]
c=2b-a
[tex]b^2+(2b-a)^2=a^2\\
5b=4a\\
b= \frac{4a}{5} \\
c= \frac{8a}{5} -a= \frac{3a}{5} \\
sin2x=2 \cdot sinx\cdot cosx=2\cdot \frac{c}{a} \cdot \frac{b}{a}= \frac{24}{25}
[/tex]
In concluzie, sin(BAD)=24/25.
