Question

answer this.........​

Answer 1

√12×12
$prime \: factorization \: of \: 432 \\ 12 {}^{2}\times 3 \\ = 12 \times \sqrt{3} \\ = 12 \times 1.73 \\ = 20.78.....$

Answer 2

see the attachment.

When decimal comes, you can add two zeroes at a time, like two zeroes added to 32 to make it 3200 after the decimal comes in 20.7...

Stop at two decimals, at 20.78

numbers are getting bigger after that.