Pole trapezu = [tex]\frac{(a+b)*h}{2}[/tex]
a) [tex]P=\frac{(8+12)*4}{2} =\frac{20*4}{2} =\frac{80}{2} =40cm^2[/tex]
b) [tex]P = \frac{(9+14)*7}{2} =\frac{23*7}{2} =\frac{161}{2} =80,5cm^2[/tex]
c) [tex]P=\frac{(7+16)*10}{2} =\frac{23*10}{2} =\frac{230}{2} =115cm^2[/tex]
d) [tex]P = \frac{(7,1+5,7)*1,5}{2} =\frac{12,8*1,5}{2} =\frac{19,2}{2} =9,6cm^2[/tex]