Width of rectangle: 20-5 = 15m.

Original garden area: 20x 15 = 300m2.

4.( 1)50x(50-2)=2400 square meters

(2)(50+2 x2)x(50+2 x2)-50x 50 = 4 16 m2

The total area of 5.80 sheets of paper is 80x2= 160 cm2.

Because 12x 12= 144, 13x 13= 169.

So the side length of a square is 12 cm.

Circumference12x4 = 48cm