Question

a farmer plants a square block of trees. he plants another 25 tress and still has a square plantation. how many trees in the new plantation

Answer 1

SInce the perfect squares are the sums of the odd numbers from 1 on up, adding 25 trees to a square plantation of 12 by 12 trees would increase the planation by 12 on two adjacent rows and 1 in the corner resulting in the growth of the plantation from 12 x 12 to 13 x 13 or 144 trees to 169 trees.
169 - 144 =25.