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 Ois the…
JEE Main 2019 — Mathematics Coordinate Geometry
2019mcqeasy
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 Ois the origin, is:
Official previous-year question
Held on 10 Jan 2019 · Verified 6 Jul 2026.
Options
A
(4,4)
B
(3,4)
C
(4,3)
D
(2,2)
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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 ΔOAB, we have OA=b=8,OB=a=6 and AB=c=(8−0)2+(0−6)2=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
I≡(a+b+cax1+bx2+cx3,a+b+cay1+by2+cy3)
⇒I≡(246(8)+8(0)+10(0),246(0)+8(6)+10(0))
⇒I=(2,2).
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