Question

va rog!!!! am nevoie de ajutor!!!!

Answer 1

Răspuns:

a)3375/2

b)9cm

Explicație pas cu pas:

Duci DM_|_AB

Atunci vom avea DM=BC=45cm

Dar stim ca mA=45 => triunghiul AMD dreptunghic isoscel => DM=AM=45cm =>AB=45+15=60cm (AM+CD)

A ABCD=(AB+CD)×BC/2=75×45/2

Ducem diagonala AC si aplicam in triunghiul ACB T.P => AC²=AB²+BC² =>

AC²=60²+45² => AC=75cm

A ACB=AB×BC/2=60×45/2

=>A ACD=A ABCD-A ACB =>

A ACD=75×45/2 - 45×60/2 =>

A ACD=45(75-60)/2 =>

A ACD=45×15/2=675/2

Notam DN_|_AC => DN×AC/2=675/2 =>

DN×AC=675 => DN×75=675 =>DN=9