Question

What's the square root 20

Answer 1

  by using calculator, these are the answers:
√20 = 4.47213595499958

√18 = 4.24264068711928

but without calculator,

√20 = √(4x5)
= √4 x √5
= 2 x √5
= 2√5

√18 = √(9x2)
= √9 x √2
= 3 x √2
= 3√2