Question

Fie ABCD un trapez isoscel cu DC=16 cm,AB= 4 cm si m(unghiuluiADC)=45grade
Calculeaza aria trapezului ABCD

Answer 1

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=$\frac{DC-AB}{2}= \frac{16-4}{2}=6cm$
B=DC, b=AB si h=AE
A=$\frac{(B+b)*h}{2}= \frac{(16+4)*6}{2}$
A=10*6=60cm²