Plz help me and plz show your work

Step-by-step explanation:

The common difference, d, is 3, because the number of squares goes up by 3 each time.

d = 3

Number of squares in nth figure is:

a(n) = 4 + d(n - 1)

4 is the initial number of squares, d is how many it goes up each time, and we take n-1 because you need to account for the initial number of squares.

a(n) = 4 + d(n - 1)

For n = 200

a(n) = 4 + d(n - 1)

a(200) = 4 + 3(200-1)

a(200) = 4 + 3(199)

a(200) = 4 + 597

a(200) = 601