Section Formula CBSE NCERT Solutions Chapter 7 Exercise 7.2 Question 3
3. To conduct sports day activities, in your rectangular shaped school ground ABCD, lines have been drawn with chalk powder at a distance of 1 m each. 100 flower pots have been placed at a distance of 1 m from each other along AD. Niharika runs
of the distance AD on the 2nd line and posts a green flag. Preet runs
of 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?
Solution:
Niharika runs
of the distance AD on the 2nd line and posts a green flag. There are 100 flower pots. It means, she stops at 25th flower pot. Therefore, the coordinates of point where she stops are (2 m, 25 m).
Preet runs
of the distance AD on the eighth line and posts a red flag. There are 100 flower pots. It means, she stops at 20th flower pot. Therefore, the coordinates of point where she stops are (8 m, 20 m).
Using Distance Formula to find distance between points (2 m, 25 m) and (8 m, 20 m), we get
Rashmi posts a blue flag exactly halfway the line segment joining the two flags. Using section formula to find the coordinates of this point, we get
Therefore, coordinates of point, where Rashmi posts her flag are (5, 45/2).
It means she posts her flag in 5th line after covering 45/2 = 22.5 m of distance.
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