Q) In what ratio does the X-axis divide the line segment joining the points(2, – 3) and (5, 6)? Also, find the coordinates of the point of intersection.
Ans: Let’s draw the diagram to solve:
(i) Ratio of division:
We know that the value of y-coordinate on X- axis is always 0
It is given that X-axis intersects the line connecting points P &Q, hence the value of y-coordinate of intersection point A will be 0.
∴ we can consider the coordinates of point A as (x, 0)
Next, let’s consider that the line PQ is divided in the ratio of m : n.
We know that, by section formula, if a point (x, y) divides the line joining the points (x1, y1) and (x2, y2) in the ratio m : n, then the coordinates of intersection point (x, y) is given by:
,
Here, it is given that
P (2, – 3) = (x1, y1)
Q (5, 6) = (x2, y2),
Let’s consider line is divided in the ratio of m : n
Hence the y-coordinate of point A:
y =
∴ 0 =
∴ – 3 m + 6 n = 0
∴ 3 m = 6 n
∴ m = 2 n
∴ m : n = 2 : 1
Therefore, the line is divided in the ratio of 2 : 1.
(ii) Coordinates of intersection point:
From the section formula, let’s find the value of x coordinate:
x =
∴ x =
∴ x = = 3
Since, value of y coordinate is 0 (being on X-axis)
Therefore the coordinates of intersection point A are (3, 0).
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