RD Chapter 14 Co ordinate Geometry Ex 14.5 Solutions
Question - 11 : - For what value of ‘a’ the points (a, 1), (1, -1) and (11, 4) are collinear?
Answer - 11 : - Let the vertices of ∆ABC are A (a, 1), B (1, -1) and C (11, 4)
Question - 12 : - Prove that the points (a, b), (a1, b1) and (a – a1, b – b1) are collinear if ab1 = a1b.
Answer - 12 : -
Question - 13 : - If the vertices of a triangle are (1, -3), (4, p) and (-9, 7) and its area is 15 sq. units, find the value(s) of p. [CBSE 2012]
Answer - 13 : - The vertices of a triangle are (1, -3), (4, p) and (-9, 7) and area of triangle = 15 sq. units
Question - 14 : - If (x, y) be on the line joining the two points (1, -3) and (-4, 2), prove that x + y + 2 = 0.
Answer - 14 : -
Point (x, y) be on the line joining the two points (1, -3) and (-4, 2)
Points (x, y), (1, -3) and (-4, 2) are collinear
Let the points (x, y) (1, -3) and (-4, 2) are the vertices of a triangle, then
Question - 15 : - Find the value of k if points (k, 3), (6, -2) and (-3, 4) are collinear. [CBSE 2008]
Answer - 15 : - Let the points (k, 3), (6, -2) and (-3, 4) be the vertices of a triangle, then
Question - 16 : - Find the value of k, if the points A (7, -2), B (5, 1) and C (3, 2k) are collinear. [CBSE 2010]
Answer - 16 : -
Points A (7, -2), B (5, 1) and C (3, 2k) are collinear
area of ∆ABC = 0
Question - 17 : - If the point P (m, 3) lies on the line segment joining the points A (−2/5 , 6) and B (2, 8), find the value of m.
Answer - 17 : -
Question - 18 : - If R (x, y) is a point on the line segment joining the points P (a, b) and Q (b, a), then prove that x + y = a + b. [CBSE 2010]
Answer - 18 : -
Point R (x, y) lies on the line segment joining the points P (a, b) and Q (b, a)
Area of ∆PRQ = 0
Question - 19 : - Find the value of k, if the points A (8, 1), B (3, -4) and C (2, k) are collinear. [CBSE 2010]
Answer - 19 : -
The points A (8, 1), B (3, -4) and C (2, k) are collinear
Area of ∆ABC = 0
Question - 20 : - If a ≠ b ≠ 0, prove that the points (a, a²), (b, b²), (0, 0) are never collinear. [CBSE 2017]
Answer - 20 : -