The perimeter of the first figure is the perimeter of two circles with a diameter of 2, that is, 2*2*π= 12.56CM.

The perimeter of the second figure is equal to four semicircles with the diameter of 1 +4cm, that is, 4 *1* π/2+4 =10.28cm. ..

The perimeter of the third figure consists of two identical parts.

The circumference of the upper half is the circumference of a circle with a diameter of 1 plus the circumference of a cell with a diameter of 2 cm.

That is,1* π+2 * π/4 = 3.14+1.57 = 4.71,and then multiply by 2 to get 9.42CM.

The perimeter of the fourth figure is equal to 1 circles with a diameter of 1 plus a semicircle with a diameter of 2, that is,1* π+2 * π/2 = 6.28cm..

Is this a four-digit number? I have four such numbers here.