Find the fourth proportional to 7, 13 and 21.
Answer & explanation
Correct answer: option 3
Given,
7 : 13 :: 21 : x
The fourth proportion x,
⇒ 7x = 21 x 13,
⇒ 7x = 273,
⇒ x = 39.
Find the fourth proportional to 7, 13 and 21.
Correct answer: option 3
Given,
7 : 13 :: 21 : x
The fourth proportion x,
⇒ 7x = 21 x 13,
⇒ 7x = 273,
⇒ x = 39.