Given length of cardboard including margin = 8 cm
Breadth of the cardboard including margin = 5 cm
Area of the cardboard including the margin = 8 cm x 5 cm = 40 c m2
From the figure, we can observed that,
New length of the painting without margin = 8 cm – (1.5 cm + 1.5 cm)
= (8 – 3) cm
= 5 cm
New breadth of the painting without margin = 5 cm – (1.5 cm + 1.5 cm)
= (5 – 3) cm
= 2 cm
Area of the painting not including the margin = 5 cm x 2 cm = 10 cm2
Hence, Area of the margin = Area of the cardboard including the margin – Area of the painting
= (40 – 10) cm2
= 30 cm2