PLEASE HELP ME!!!!!!!

Answer:
i6 sqrt 5
Step-by-step explanation:
It cannot be 12i sqrt 5 as this is 26.8326....
it cannot be 18i sqrt 5 as this is 40.249...
It cannot be 8i sqrt 5 as this is 17.888....
It cnanot be 8i sq rt 10 as this is 25.298....
i6 sq rt 5 = sqrt -180