Given, the perpendicular from the origin to the line y = mx + c meets it at the point (–1, 2)
∴ 2 = m (–1) + c ... (i)
⇒ c – m = 2
Slope of the perpendicular OR =

2−0

−1−0

= - 2 ... (ii)
Slope of the line y = mx + c is m
⇒ m =

1

2

(from (ii))
Put the value of m in (i), we get c −

1

2

= 2 ⇒ c = 2 +

1

2

=

5

2

.