1 00:00:00,150 --> 00:00:06,630 All right, so let's read the question we need to identify the number of line segments in this figure 2 00:00:06,630 --> 00:00:09,780 that that is given the what are the points over here? 3 00:00:10,020 --> 00:00:16,950 We can see that the marked points are A, B, C, D and E, we could mark an infinite number of points 4 00:00:16,950 --> 00:00:17,820 in between them. 5 00:00:18,100 --> 00:00:18,590 All right. 6 00:00:18,720 --> 00:00:22,960 But the question asks us to identify the number of line segments in this figure. 7 00:00:22,980 --> 00:00:23,340 Right. 8 00:00:23,640 --> 00:00:23,990 All right. 9 00:00:24,240 --> 00:00:28,880 Now, let's try to do that starting at M, how many line segments can I draw? 10 00:00:29,250 --> 00:00:33,180 I could have A, B, C, D or E, right. 11 00:00:33,780 --> 00:00:34,590 Is a line segment. 12 00:00:34,750 --> 00:00:35,090 Right. 13 00:00:35,370 --> 00:00:37,290 But let me just quickly right over here. 14 00:00:37,660 --> 00:00:41,640 So this would be a red line segment a B similarly. 15 00:00:41,820 --> 00:00:42,870 What is the line segment. 16 00:00:42,870 --> 00:00:43,430 Easy. 17 00:00:43,810 --> 00:00:45,260 I take only this much. 18 00:00:45,570 --> 00:00:47,150 This is line in segment easy. 19 00:00:47,490 --> 00:00:53,660 Similarly I have D, which is also a line segment and I have E which is also a line segment. 20 00:00:53,670 --> 00:00:54,140 All right. 21 00:00:54,480 --> 00:00:58,530 So I can see that I have four line segments over here. 22 00:00:59,830 --> 00:01:07,450 Right now, let me start from B and draw all the possible line segments starting at B, I have B, C 23 00:01:07,750 --> 00:01:14,460 Beauty and B and all that, we are not including B because we have already considered it over here. 24 00:01:14,470 --> 00:01:14,690 Right. 25 00:01:14,710 --> 00:01:18,190 So we don't want to count the same line segment two times. 26 00:01:18,490 --> 00:01:25,300 So we don't include B, which is the same as A, B except B, what are the other line segments that 27 00:01:25,300 --> 00:01:29,620 we get starting from B we have B, C, that's this part over here, right. 28 00:01:29,620 --> 00:01:35,980 This is B, C, we have Beardie, that's this line segment and we have B, E, right. 29 00:01:36,310 --> 00:01:38,920 But that is how many line segments. 30 00:01:38,920 --> 00:01:40,240 That's three line segments. 31 00:01:40,240 --> 00:01:40,600 Right. 32 00:01:41,840 --> 00:01:50,630 All right, now, starting at point C, I could get how many line segments I can get two line segments 33 00:01:50,840 --> 00:01:56,360 and starting in point B, I can get one line segment starting in point C, I can get this one that's 34 00:01:56,360 --> 00:02:02,930 KDDI or C, E, and I am not counting B because CBS already counted over here. 35 00:02:03,410 --> 00:02:07,090 I am not counting C because he is already counted over here. 36 00:02:07,280 --> 00:02:11,690 So I do not want to count the same line segment two times because then I would get the wrong answer. 37 00:02:12,020 --> 00:02:12,410 All right. 38 00:02:12,630 --> 00:02:19,430 So I can get two new line segments starting at C and starting a D, I get only D, all the other ones 39 00:02:19,430 --> 00:02:24,350 B, C, DB and B are already counted like the same as eighty. 40 00:02:24,680 --> 00:02:31,040 DB is the same as Beedi and you have already counted three, which is the same as DC, so we don't count 41 00:02:31,040 --> 00:02:31,250 them. 42 00:02:31,490 --> 00:02:34,970 So there's only one new we get one new line segment that we get. 43 00:02:35,270 --> 00:02:35,740 All right. 44 00:02:36,590 --> 00:02:42,500 Now the question asks us the total number of line segments that we can form out of this given figure. 45 00:02:42,780 --> 00:02:48,650 So that is equal to or plus three plus two plus one or three, two and one. 46 00:02:48,650 --> 00:02:54,110 And if you add this four plus three, seven, seven plus two is nine, nine plus one is ten. 47 00:02:54,110 --> 00:02:55,990 And that is your answer.