The fourth proportional to 12, 20 and 30 is? Choices:
A) 21  B) 66  C) 55  D) 50  E) 61
(20*30)/12= 
<gadget id="calculator">(20*30)/12</gadget>
<output>50</output>
50   Answer:50
<result>D</result>
The fourth proportional to 12, 20 and 30 is?