A phone tree is used to contact families and relatives of Ali's deceased coworker. Ali decided to call 3 families. Then each family calls 3 other families, and so on. How many families will be notified during the fourth round of calls?
In the first round, there are 3 families called.
In the second round, there are 3 x 3 = 
<gadget id="calculator">3*3</gadget>
<output>9</output>
9 families called.
In the third round, there are 9 x 3 = 
<gadget id="calculator">9*3</gadget>
<output>27</output>
27 families called.
In the fourth round, there are 27 x 3 = 
<gadget id="calculator">27*3</gadget>
<output>81</output>
81 families called.

<result>81</result>