√45 = √$9\ast 5$ = 3√5

√98 = √$49\ast 2$ = 7√2

√20 = √$4\ast 5$ = 2√5

√450 = √$225\ast 2$ = 15√2

4√18 = 4√$9\ast 2$ = 12√2

1/3√54 = $1/3$√$9\ast 6$ = 3√6

1,5√32 = 1,5√$16\ast 2$ = 4√2