The forth proportional to 5,10,20 is?
Options:	A) 20	B) 40	C) 45	D) 80	E) 35
Let the fourth proportional to 5,10,20 be x   then 5:10::20:x   5x = 10*20   x = 40   Answer is 40
<result>B</result>
The forth proportional to 5,10,20 is?