Wzor na pole trapezu:
[tex]P=\frac{(a+b)*h}{2}[/tex]
a = 3cm
b = 3cm+3cm=6cm
h = 4cm
[tex]P=\frac{(3cm+6cm)*4cm}{2} = \frac{9cm*4cm}{2} = 9cm*2cm=18cm^2[/tex]
