The fourth proportional to 75, 192 and 200 is equal to fourth proportional to 90, 384 and Q. Find the value of Q.
1). 100
2). 108
3). 120
4). 126
Fourth proportional to 75, 192 and 200 will be R, if
75/192 = 200/R
⇒ R = (200 × 192)/75
Fourth proportional to 90, 384 and Q will be R, if
90/384 = Q/R
⇒ R = (384Q/90)
⇒ (384Q/90) = (200 × 192)/75
⇒ Q = (100 × 90)/75 = 120