Question

Fie triunghiul DEF cu m(D)=90 di DM perpendicular pe EF .
Daca DE=30 cm si EF= 50 cm ,calculati lungimile EF, DF si DM

Answer 1

Facem teorema lui Pitagora in ΔDFE, DF²=50²-30²=2500-900=1600 => DF=√1600= 40 cm
Aria ΔDFE este $\frac{DE x DF}{2}$=$\frac{30 x 50}{2}$=750 cm²
Tot aria ΔDFE este $\frac{DM x FE}{2}$ =$\frac{DM x 50}{2}$ => 750=25DM => DM=30 cm
Si EF e 50, ti-l da in cerinta..