1 00:00:00,880 --> 00:00:10,120 Let's do this question, find this ratio that is 80 of ABCDE to the area of Triangle Deep Cube, that 2 00:00:10,120 --> 00:00:13,890 is this triangle over here to the area of Triangle dequeue. 3 00:00:14,140 --> 00:00:15,610 That's this triangle over here. 4 00:00:15,970 --> 00:00:22,300 Alright, pause the video, give it a try and then let's do it together and do try to use graphical 5 00:00:22,300 --> 00:00:26,050 division method to find this answer because it'll save you a lot of time. 6 00:00:26,800 --> 00:00:27,280 All right. 7 00:00:27,430 --> 00:00:28,060 We we're back. 8 00:00:28,210 --> 00:00:29,650 I hope you've given it a try. 9 00:00:29,830 --> 00:00:31,490 Let's do it together now. 10 00:00:31,660 --> 00:00:36,520 Over here, you can see that it is 20 and DC is 20 centimeter. 11 00:00:36,670 --> 00:00:39,360 And it's given that this angle is 90 degrees. 12 00:00:39,610 --> 00:00:42,190 So ABCDE is a square. 13 00:00:42,190 --> 00:00:42,550 Right. 14 00:00:42,850 --> 00:00:46,210 And we know that area of a square is side square. 15 00:00:46,330 --> 00:00:49,600 So area of ABCDE is 20 to 20. 16 00:00:49,900 --> 00:00:50,890 That's four hundred. 17 00:00:51,280 --> 00:00:51,750 All right. 18 00:00:52,060 --> 00:00:59,980 Now let's drop it perpendicular from B, so Apison that means B also is equal to 10 or P is the midpoint 19 00:00:59,980 --> 00:01:00,640 of Abe. 20 00:01:00,680 --> 00:01:01,140 All right. 21 00:01:01,300 --> 00:01:06,070 Now, let me drop it perpendicular from B to let me see at our. 22 00:01:06,400 --> 00:01:06,940 All right. 23 00:01:07,630 --> 00:01:13,630 Now you can see that B R has divided this square into two parts of equal area. 24 00:01:13,810 --> 00:01:20,120 Remember that similar to the first problem we discussed in the introduction to graphical division. 25 00:01:20,410 --> 00:01:20,880 All right. 26 00:01:21,070 --> 00:01:27,250 So we have a party and BCR and each of these will be of equal area. 27 00:01:27,460 --> 00:01:30,240 So you have two hundred over here and two hundred over here. 28 00:01:30,670 --> 00:01:31,150 All right. 29 00:01:31,480 --> 00:01:34,300 Now, let's see, Beardie. 30 00:01:34,300 --> 00:01:35,960 There is a nine party over here. 31 00:01:36,130 --> 00:01:39,670 This is a diagonal to A, B, R, B, right. 32 00:01:39,880 --> 00:01:44,710 So this two hundred is divided into two by P.E.T.. 33 00:01:44,710 --> 00:01:45,060 Right. 34 00:01:45,190 --> 00:01:53,020 You have triangle apre and triangle pedia and each of these will be of hundreds and hundreds centimetres 35 00:01:53,020 --> 00:01:53,920 square each. 36 00:01:54,370 --> 00:01:54,750 Right. 37 00:01:55,820 --> 00:01:57,300 So let's write that over here. 38 00:01:57,530 --> 00:02:02,720 You have a pretty standard annual periodical to handle, all right. 39 00:02:02,900 --> 00:02:07,900 Now, over here, it's given that QCA right there for Cubie also will be 10. 40 00:02:08,060 --> 00:02:08,450 That is. 41 00:02:08,450 --> 00:02:15,350 Q is the midpoint of beseen now from Q Let's draw a perpendicular touching 80 at S right. 42 00:02:15,650 --> 00:02:22,910 So over here you can see that esq, you see them will have an area of two hundred in a similar manner 43 00:02:22,910 --> 00:02:23,960 that we saw over here. 44 00:02:24,200 --> 00:02:26,840 And Kudi is a diagonal to skew. 45 00:02:27,560 --> 00:02:34,250 Therefore the area of Triangle Deek you see will be half of two hundred that is handed over here. 46 00:02:34,520 --> 00:02:34,900 Right. 47 00:02:35,240 --> 00:02:37,220 All right, let's proceed. 48 00:02:37,460 --> 00:02:47,540 Now you can see that or b, b, q that's all we BQ this is forming one by fourth of the area of the 49 00:02:47,550 --> 00:02:48,000 square. 50 00:02:48,020 --> 00:02:48,730 Can you see that. 51 00:02:49,250 --> 00:02:49,820 Why is that. 52 00:02:49,830 --> 00:02:52,000 So let's take any one over here. 53 00:02:52,010 --> 00:02:59,870 For example, you take P r we have seen that BBC R is half of the area of the square and over here again 54 00:03:00,020 --> 00:03:01,280 you divide it into two. 55 00:03:01,280 --> 00:03:01,630 Right. 56 00:03:02,030 --> 00:03:04,010 So this part will be half of half. 57 00:03:04,220 --> 00:03:12,440 That is one by four of the area of the square will be P q OK, so the area of barbecue will be one by 58 00:03:12,440 --> 00:03:15,310 four in the form that that's equal to a hundred. 59 00:03:15,680 --> 00:03:16,130 All right. 60 00:03:16,280 --> 00:03:19,850 Now P Q is a diagonal to be Q Right. 61 00:03:20,000 --> 00:03:23,270 And hence P Q is dividing it into two equal areas. 62 00:03:23,540 --> 00:03:27,440 Therefore the area of P, Q, B is half of hundert. 63 00:03:27,740 --> 00:03:29,660 That is equal to 50. 64 00:03:29,900 --> 00:03:30,380 Right. 65 00:03:30,410 --> 00:03:31,820 So let's mark that over here. 66 00:03:32,120 --> 00:03:34,330 Now let's try to find the answer. 67 00:03:34,520 --> 00:03:36,020 What would be the area of deep. 68 00:03:36,020 --> 00:03:42,020 Q That would be four hundred minus under plus 50 plus hundred. 69 00:03:42,020 --> 00:03:42,240 Right. 70 00:03:42,260 --> 00:03:46,920 So you just need to subtract these three from four hundred to get the deep. 71 00:03:46,940 --> 00:03:49,690 Q All right, let's write that over here. 72 00:03:49,910 --> 00:03:56,480 The area ODP, you will be four hundred minus hundred, minus hundred minus fifty and therefore the 73 00:03:56,480 --> 00:04:04,430 required area or the required ratio over here will be one that is to 150 is two hundred or that is the 74 00:04:04,430 --> 00:04:05,270 area of the square. 75 00:04:05,270 --> 00:04:06,230 We have that over here. 76 00:04:06,560 --> 00:04:08,630 150 is the area of deep. 77 00:04:08,630 --> 00:04:11,120 Q When you do this you will get one fifty. 78 00:04:11,270 --> 00:04:11,640 Right. 79 00:04:11,870 --> 00:04:15,240 And the area of Triangle DC. 80 00:04:15,260 --> 00:04:17,000 Q That would be a hundred. 81 00:04:17,750 --> 00:04:24,560 Alright, so you can note over here that using graphical division method we were able to do this question 82 00:04:24,710 --> 00:04:25,610 very fast.