It is a mixed series The letters at the odd-numbered positions form one series and the letters at the even-numbered positions form another series Consider the letter series S T V ___ C In this series between S and T no letter is skipped Between T and V one letter U is skipped Hence after V we should skip two letters W and X to find the missing letter Therefore the answer is Y After Y if we skip three letters (i.e. Z, A and B) we get the letter C which is the next letter pf the series The other series is C B A Z These are all consecutive letters in the reverse order The pattern can be indicated as follows.
For parallelograms we can use the formula of rectangles. It is a $\displaystyle 3 \, \times \, 3 \, gird, \, hence \, \frac{3 \, \times \, 4}{3 \, \times \, 4} \, \times \frac{3 \, \times \, 4}{3 \, \times \, 4} \, = \, 36$