Question

The number of parts into which the plane is divided by $5$ distinct st. lines drawn in the plane through a point is

• A. $5$
• B. $10$
• C. $15$
• D. $20$

Answer 1

Answer: (B)

$10$

When $2$ distinct lines are drawn from a point, the number of parts the plane gets divided into are $4$.

When the number of lines is extended to $3$, we get $6$ parts.

Hence $n$ lines divide a plane in $2n$ parts.

similarly, when the lines drawn are $5$, the number of parts add up to $10$.