# Lecture-3

00:00:20 Derivation of Section Formula

00:13:03 NCERT Exercise 7.2 Questions 1 Find the coordinates of the point which divides the join of (–1, 7) and (4, –3) in the ratio 2 : 3.

00:15:13 NCERT Exercise 7.2 Questions 2 Find the coordinates of the points of trisection of the line segment joining (4, –1) and (–2, –3).

00:21:22 Derivation of Mid-point formula

00:29:13 NCERT Exercise 7.2 Questions 3 To conduct Sports Day activities, in your rectangular shaped school ground ABCD, lines have been drawn with chalk powder at a distance of 1m each. 100 flower pots have been placed at a distance of 1m from each other along AD, as shown in Fig. 7.12. Niharika runs 1/4th the distance AD on the 2nd line and posts a green flag. Preet runs 1/5th the distance AD on the eighth line and posts a red flag. What is the distance between both the flags? If Rashmi has to post a blue flag exactly halfway between the line segment joining the two flags, where should she post her flag?

00:35:33 NCERT Exercise 7.2 Questions 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.

00:38:53 NCERT Exercise 7.2 Questions 7 Find the coordinates of a point A, where AB is the diameter of a circle whose centre is (2, – 3) and B is (1, 4).

00:45:23 NCERT Exercise 7.2 Questions 6 If (1, 2), (4, y), (x, 6) and (3, 5) are the vertices of a parallelogram taken in order, find x and y.