Lets solve all of these:-
#1
√361 = 361 · 2
?
√361 = 361 · 2
√361 = 19
361 · 2 = 722
19 ≠ 722
So this equation is not true
#2:-
√361 = 19²
?
√361 = 19²
√361= 19
19² = 19 · 19 = 361
19 ≠ 361
So this equation is not true
√361 = 361 ÷ 2
?
√361 = 361 ÷ 2
√361 = 19
361 ÷ 2 = 180.5
√361 ≠ 361 ÷ 2
So this equation is not true
√361 = √19²
√361 = 19
√19² = 19
19 = 19
SO the last one is right. Hope I helped ya!! xD