40
Step-by-step explanation
Step 1
a)initially we have 8 dots
after that
in step 2, we have a new row and , now there are 8 dots per row, so
in step 3, we should have
and
as we can see, the rule works
Step 2
now, to find the patter in step 4, just apply
and
finally, to know the number of dots
Multiply the number of row, by the number of dots per row, so
therefore, the answer is 40
I hope this helps you