Notice this is a geometric progression since each number multiplied by some factor equals the next number in the sequence, in this case,
Then by applying the formula for sum to infinity of a geometric progression,
8• (5+x) < 56
That is the equation
One is 3pi/2 - 2pi = -pi/2
also -7pi/2
Note that the measurements of the side of the squares are the same.
Area = base x height
Area = length x width
The area given is 400
Root 400 to get the length of the sides
√400 = 20
20 in. is your side measurement
hope this helps