If the line 3 x + 4 y - 24 = 0 intersects the x -axis is at the point A and the y -axis at the point B ,…

If the line 3x+4y-24=0 intersects the x-axis is at the point A and the y-axis at the point B, then the incentre of the triangle OAB, where O is the origin, is:
  1. 4, 4 
  2. 3, 4
  3. 4, 3
  4. 2, 2

Solution

The x intercept of the line 3x+4y-24=0 can be obtained by putting y=0 i.e. 3x-24=0

x=8

Hence, the point A is 8, 0.

Now, the y intercept of the line 3x+4y-24=0 can be obtained by putting x=0 i.e. 4y-24=0

y=6

Hence, the point B is 0, 6.

In OAB, we have OA=b=8, OB=a=6 and AB=c=8-02+0-62=64+36=10 units.

And, we know that the co-ordinates of incentre I of a triangle with vertices x1, y1, x2, y2 and x3, y3 and having length of the sides opposite to these vertices as a, b and c, respectively,  is

Iax1+bx2+cx3a+b+c, ay1+by2+cy3a+b+c

I68+80+10024, 60+86+10024

I=2, 2.

Asked in: JEE Main 2019 (10 Jan Shift 1)

Practice more Straight Lines questions on Aicharya