Question

If SQUARE is coded as 9E7R1A, RECTANGLE is coded as 8E5L3G0N1, then how will you code QUADRILATERAL?

Answer 1

Hmmm. E seems to be encoded as A,E and 1
so not just a replacement cipher.
I guess your guess is a good as mine.

Answer 2

1. the word square has six alphabets so do the coded form of this word
2. notice ARE is spelled backwards in coded form after one number?the same is with rectangle

So if we apply the same rule to quadriletral wil be 7l2a6r8t5e7 with 13 character and last digits spelled backwards after each number. this should be the answer(i dont know he meaning of numbers)

Answer 3

First you write _E_R_A_ (last 3 letters of square backward way)
Now remaining letters are SQU (place of S is 19, Q is 17 and U is 21 on alphabetical order, so put 9, 7 and 1 in blanks)
SQUARE becomes 9E7R1A
Similarly RECTANGLE becomes 8E5L3G0N1.
QUADRILATERAL becomes 7L1A1R4E8T9A2.