Length of the rectangle = [20 − (3.5 + 3.5)] metres = 13 m

Circumference of 1 semi-circular part = πr = (22/7 x 3.5)m = 11 m

Circumference of both semi-circular parts = (2 × 11) m = 22 m

Perimeter of the garden = AB + Length of both semi-circular regions BC and DA + CD

= 13 m + 22 m + 13 m = 48 m

Area of the garden = Area of rectangle + 2 × Area of two semi-circular regions