Question

Find the third proportional to the following:

2.4, 3.6

Answer 1

Let x be the third proportional to 2.4, 3.6.

Third proportional to 2.4, 3.6 is the same thing as fourth proportional to 2.4, 3.6, 3.6, then

2.4 : 3.6 :: 3.6 : x

⇒ `2.4/3.6 = 3.6/x`

⇒ 2.4 × x = 3.6 × 3.6

⇒ 2.4x = 12.96

⇒ x = `12.96/2.4`

⇒ x = 5.4