Odpowiedź:
a) a = 120 mm = 12 cm
b = 40 mm = 4 cm
h = 3 cm
P = [(a+b) *h] /2
P = [(12 cm + 4 cm) * 3 cm] /2 = (16 cm * 3 cm) / 2 = 48 cm²/2 = 24 cm²
b) a = 1dm = 10cm
b = 70 mm = 7 cm
h = 40mm = 4 cm
P = [(a+b) *h] /2
P = [(10 cm + 7 cm) * 4 cm] /2 = (17 cm *4 cm) / 2 = 68 cm² / 2 = 34 cm²