Answer
$7.746i$
Work Step by Step
Step 1: $\sqrt {-60}$
Step 2: $\sqrt {-1\times60}$
Step 3: $\sqrt {-1}\times\sqrt {60}$
Step 4: $\sqrt {-1}\times\sqrt {4\times15}$
Step 5: $\sqrt {-1}\times\sqrt 4\times\sqrt {15}$
Step 6: As $i=\sqrt {-1}$,$\sqrt {-1}\times\sqrt 4\times\sqrt {15}=i\times 2\times\sqrt {15}$.
Step 7: $i\times2\times\sqrt {15}=2i\sqrt {15}\approx7.746i$
