**NCERT solutions for class 10 Maths**

**Chapter 7**

**Coordinate Geometry**

**Exercise 7.4**

**Ex 7.4 Question 1.**

** Determine the ratio in which the line 2x + y – 4 = 0 divides the line segment joining the points A(2, –2) and B(3, 7).**

**Solution: **

**Ex 7.4 Question 2.**

** Find the relation between x and y if the points (x, y), (1, 2) and (7, 0) are collinear.**

**Solution:**

**Ex 7.4 Question 3.**

** Find the centre of a circle passing through points (6, -6), (3, -7) and (3, 3).**

**Solution:**

**Ex 7.4 Question 4.**

** The two opposite vertices of a square are (-1, 2) and (3, 2). Find the coordinates of the other two vertices.**

**Solution:**

**Ex 7.4 Question 5.**

** The class X students of a secondary school in Krishinagar have been allotted a rectangular plot of land for their gardening activity. Saplings of Gulmohar are planted on the boundary at a distance of 1 m from each other. There is a triangular lawn in the plot as shown in the fig. 7.14. The students are to sow the seeds of flowering plants on the remaining area of the plot.**

**(i) Taking A as origin, find the coordinates of the vertices of the triangle.**

**(ii) What will be the coordinates of the vertices of triangle PQR if C is the origin?**

**Also calculate the areas of the triangles in these cases. What do you observe?**

**Solution:**

**Ex 7.4 Question 6.**

** The vertices of a ∆ ABC are A (4, 6), B (1, 5) and C (7, 2). A line is drawn to intersect sides AB and AC at D and E respectively, such that . Calculate the area of the ∆ ADE and compare it with area of ∆ ABC. (Recall Theorem 6.2 and Theorem 6.6)**

**Solution:**

**Ex 7.4 Question 7.**

**Let A (4, 2), B (6, 5) and C (1, 4) be the vertices of ∆ ABC.**

**(i) The median from A meets BC at D. Find the coordinates of point D.**

**(ii) Find the coordinates of the point P on AD such that AP : PD = 2 : 1.**

**(iii) Find the coordinates of point Q and R on medians BE and CF respectively such that BQ : QE = 2:1 and CR : RF = 2 : 1.**

**(iv) What do you observe?**

**[Note : The point which is common to all the three medians is called the centroid**

**and this point divides each median in the ratio 2 : 1.](v) If A (x _{1}, y_{1}), B (x_{2}, y_{2}) and C (x_{3}, y_{3}) are the vertices of triangle ABC, find the coordinates of the centroid of the triangle.**

**Solution:**

**Ex 7.4 Question 8.**

**ABCD is a rectangle formed by the points A (-1, – 1), B (-1, 4), C (5, 4) and D (5, -1). P, Q, R and S are the midpoints of AB, BC, CD and DA respectively. Is the quadrilateral PQRS a square? a rectangle? or a rhombus? Justify your answer.**

**Solution:**