Answer:
152 shaded squares
Explanation:
The first square has 12 shaded blocks, the second square has 16, the third box has 20 shaded blocks so I know that the shaded box's are increasing by 4 each figure and the first box starts with 12. So I multiplied 4 by 35 and got 140 I then add the 12 that figure 1 started with and got 152. So the 35th box has 152 shaded squares.