Step-by-step explanation:
x = 1.21212121.....
100x = 121.21212121...
Therefore 99x = 120 and x = 120/99 = 40/33.
Ok I think it means that the length

of the rectangle is 2 m more than is width

...
The area is A=

so:

Solving this equation (using the quadratic formula) you get 2 solutons. The only acceptable is the positive one, i.e.

, the length will then be

.
Let x, x+1,x+2, x +3 are the <span>numbers
so
</span>x + x +1 + x +2 +x +3 = 198
4x + 6 = 198
4x =198-6
4x = 192
x = 192/4
x = 48
x + 1 = 48 + 1 = 49
x + 2 = 48 + 2 = 50
x + 3 = 48 + 3 = 51
proof
48 + 49 + 50 + 51 = 198
so the numbers are 48, 49, 50, 51
fourth number in this sequence is 51