ABC:14::BCD:___?

2^2+3^2+4^2=4+9+16=29

How it's 29 please explain

@Vemula Gopal Suppose A as 1 square (also written as 1^2 which is equal to 1) B as 2 square (2^2 equals 4) C as 3 square (3^2 equals 9) A+B+C= 1^2 + 2^2 + 3^2 = 1+4+9 = 14 for BCD, we already know the values of B and C the next number that comes in this order is 4 square (let's take it as D) B+C+D= 2^2 + 3^2 + 4^2 = 4+9+16 = 29 Hence, ABC:14 :: BCD:29

How it came explain sir