Coordinate Geometry Class 10 Exercise 7.2: Class 10 Maths Chapter 7 Exercise 7.2 introduces students to practical applications of dividing line segments in coordinate geometry, building directly on the previous exercise's concepts.
This exercise contains 10 questions with 5 supporting examples, progressing from basic internal division problems to more challenging ones involving external division, midpoints, and verifying ratios or collinearity of points.
Questions like finding coordinates of points dividing joins in simple ratios, determining ratios from given points, or solving real-life scenarios such as path division help develop analytical skills essential for board exams, where Q2, 5, 8, and 9 often pose greater difficulty requiring careful visualisation through sketches.
Solve the following Questions.
1. Find the coordinates of the point which divides the join of (- 1, 7) and (4, - 3) in the ratio 2:3.
Answer:
Let P(x, y) be the required point. Using the section formula,
8. If A and B are (–2, –2) and (2, –4), respectively, find the coordinates of P such that AP = 3/7 AB and P lies on the line segment AB.
Answer:
Given the coordinates of A(−2,−2) and B(2,−4) and P is a point lies on AB. And A P = 3/7 A B
∴ B P = 4/7
Then, ratio of A P and P B = m 1 : m 2 = 3 : 4
Let the coordinates of P be ( x , y ) .
∴ x = (m 1 x 2 + m 2 x 1 ) / ( m 1 + m 2 )
⇒ x = ( 3 × 2 + 4 × ( −2 )) / (3 + 4) = ( 6 − 8) / 7 = −2 / 7
And y = (m 1 y 2 + m 2 y 1 ) / ( m 1 + m 2 )
⇒ y = ( (3 × ( −4 ) + 4 × ( −2 )) / (3 + 4) = (−12 − 8) / 7 = −20 / 7
∴ Coordinates of P = −2 / 7 , −20 / 7
9. Find the coordinates of the points which divide the line segment joining A (- 2, 2) and B (2, 8) into four equal parts.
Answer:
From the figure, it can be observed that points X,Y,Z are dividing the line segment in a ratio 1:3,1:1,3:1, respectively.
Using Sectional Formula, we get, Coordinates of X = ((1 × 2 + 3 × (−2)) / (1 + 3), (1 × 8 + 3 × 2) / (1 + 3)) = (−1, 7/2) Coordinates of Y = (2 − 2) / 2, (2 + 8) / 2 = (0,5) Coordinates of Z = ((3 × 2 + 1 × (−2)) / (1 + 3), (3 × 8 + 1 × 2) / (1 + 3) = (1, 13/2)
10. Find the area of a rhombus if its vertices are (3, 0), (4, 5), (-1, 4) and (-2,-1) taken in order. [Hint: Area of a rhombus = 1/2(product of its diagonals)]
Answer:
Let (3, 0), (4, 5), ( - 1, 4) and ( - 2, - 1) are the vertices A, B, C, D of a rhombus ABCD.