AE inaltimea, E∈DC
In triunghiul ADE, E=90 grade si D=45 grade deci A=45 grade
ADE triunghi dreptunghic isoscel decu DE=AE
DE=[tex] \frac{DC-AB}{2}= \frac{16-4}{2}=6cm [/tex]
B=DC, b=AB si h=AE
A=[tex] \frac{(B+b)*h}{2}= \frac{(16+4)*6}{2} [/tex]
A=10*6=60cm²
