Odpowiedź:
I.
P = e * f / 2
e = 18 m
f = 12 m
P = 18 m * 12 m / 2 = 216 m² / 2 = 109 m²
II.
P = e * f / 2
e = 15 dm * 2 = 30 dm
f = 12 dm * 2 = 24 dm
P = 30 dm * 24 dm / 2 = 720 dm² / 2 = 360 dm²
III.
P = a * h
a = 25 cm
h = 17 cm
P = 25 cm * 17 cm = 425 cm²