A rectangle is formed by the lines x = 0, y = 0, x = 3 and y = 4. Let the line L be perpendicular to 3x + y + 6 = 0 and divide the area of the rectangle into two equal parts. Then the distance of the point ( 12, -5 ) from the line L is equal to :
- 10
- 2 5
- 2 10
- 3 10
Answer
(3) 2 10
Solution
A line divides a rectangle into two equal areas only if it passes through its centre ( 32, 2 ).
Slope of 3x + y + 6 = 0 is −3 slope of L = 13
L: y - 2 = 13 (x - 32 )
6y - 12 = 2x - 3
2x - 6y + 9 = 0
Distance of ( 12, -5 ) from L = |2 ( 12 ) - 6(-5) + 9 | 4 + 36
= 40 40 = 40 = 2 10
Answer: (3)