**Given:** points A(2, 4, 5) and B(3, 5, 4)

**To find: **the ratio in which the line joining given points is divided by the yz-plane

**Formula used: **

**Section Formula: **

A line AB is divided by C in m:n where A(x, y, z) and B(a, b, c).

The coordinates of C is given by,

X coordinate is always 0 on yz-plane

Let Point C(0, y, z), and C divides AB in ratio k: 1

Therefore, m = k and n = 1

A(2, 4, 5) and B(3, 5, 4)

Coordinates of C using section formula:

On comparing:

\(\frac{3k+2}{k+1}\) = 0

⇒ 3k + 2 = 0(k + 1)

⇒ 3k + 2 = 0

⇒ 3k = – 2

⇒ k = \(\frac{-2}{3}\)

Hence, C divides AB externally in ratio 2 : 3