The first three terms of a proportion are 2, 10 and 20. The fourth term is? Choose the correct option:  A) 105  B) 102  C) 190  D) 100  E) 134
(10*20)/2= 
<gadget id="calculator">(10*20)/2</gadget>
<output>100</output>
100   Answer:100
<result>D</result>
The first three terms of a proportion are 2, 10 and 20. The fourth term is?