Transcription
Hello friends, welcome back to my channel. In our previous video, we completed up to question number 20. Today, we will start from question number 21.
Question number 21: Rohit's family is planning to build a concrete basketball court in their backyard. If they build a basketball court of this measurement, how many square meters will be left in the backyard for grass? It means we need to find out the area that will be left. To find its area, we have a hint here. [Music] That's done. 35 square meters is given. 1 square meter is equal to 1 square meter. 35 square meters of grass is equal to 66 - 35 square meters, which is equal to 31 square meters.
22. The area of the floor of a rectangular hall is 80 square meters. What is its perimeter if its length is 10 meters? [Music] We are given its length. We need to find the perimeter. So, for the perimeter, we need both length and width. We are given the length here. So, first, the floor is given as 80 square meters, and length * width = 80 square meters. So, the length is given as 10 meters. 10 meters * width = 80 square meters. So, width = 80 / 10 meters, and width = 8 meters. Now, we know the length and we have found the width. Now we will find its perimeter. So, perimeter = 2 * (length + width) = 2 * (10 + 8) meters = 2 * 18 meters = 36 meters.
If 2 meters is required for tying the knot at each pole, what is the length of the rope that will be required? If 2 meters is required for tying the knot at each pole, and four poles have been placed, and a rope needs to be tied around all four poles from the outside, and 2 meters of rope is required for tying the knot at each pole, then what is the total length of rope needed? For that, we will find the area of the side of the square, and we will find the length of the rope used for tying the knots, and we will add both. [Music] Length of rope required is equal to 30 multiplied by 4 (for four sides, all sides are equal because it's a square) + 2 meters for each pole. So, for four poles, 2 * 4 = 8 meters. Total length = (4 * 30) + (2 * 4) = 120 + 8 = 128 meters. 8 meters is the answer. But the answer is not given here. So, option D is the answer. Now, we will come to the point where you will solve it and the answer will not be in the given options. Whichever option is correct. The perimeter of the field is given. The length is given. We need to find the length. The total cost of fencing is rupees 2110. [Music] [Music] 140 meters. 12 is equal to 140 - 40 meters. 12. So, option is the answer. 50 meters. One day he walked around the park six times. How much distance did he walk on that day? Karan, whose square park has a side length of 50 meters. So, the perimeter is equal to 4 * 50 = 200 meters. Distance covered by Karan is equal to 200 * 6, because he took 6 rounds, so we will multiply by 6. 1200 meters.
I am question number 26. A rectangle is made up of 81 small rectangles. A large figure is formed. After removing some small rectangles from the big rectangle, the given figure is obtained. And when some rectangles are removed from that large rectangle, a figure like this is formed from the remaining rectangles. The length of a small rectangle is 3 cm, and its width is 2 cm. Now, the length of this small rectangle is 3 cm, and its width is 2 cm. So, find the area of the removed rectangles. We need to find the area of the rectangles that have been removed. Okay. We will find the area of a small rectangle, then we will find their number. If we count the number of rectangles removed, then it will be known. So, area of a small rectangle = 3 * 2 = 6 square centimeters. Number of rectangles removed. Total rectangles = 81. And when we count them, there are 62 rectangles remaining here. So, subtracting 62 from the total gives 19. Okay. So, 19 rectangles have been removed. So, total area of removed rectangles = 19 * 6 = 114 square centimeters. So, option B is the answer.
Question number 27. When two are combined, it looks like this. Okay. If the rectangle is unfolded, meaning it is opened back, what will be its area? So, we will have to do this: if we open this side and bring it back here, then this side will be equal to this. This will be equal to this, and this side given will be equal to this. So, this is 4. This is 2. And this much is 9. And from here, this much. So, this means this and this side are equal. So, 9 and this will be 4. This will be 9. This will be 9 + 2 + 4 = 15. Area. [Music] * DC. What is the length? 9 + 4. What is the length of DC? 9 + 2 + The given figure is made up of 11 squares of the same size. The area of the figure is 99 sq cm. Find the perimeter of the figure. It means 11 squares are given. Their area is 99 square centimeters. Square means the sides will be equal. So, we will divide the given area by 11 to find the area of one square, because the area of 11 squares is given here. So, first, we will find the area of one square, and then we will find its side. Once the side is known. Area of one square = 99 / 11 = 9 square centimeters. So, this is the area of one small square. If the area is 9, then what will be the side? The area of a square is found by side * side. So, this means both numbers should be equal to us. So, 9 means 3 * 3. So, side is equal to 3 cm. Now, the side is 3 cm. So, we see how many sides are there in the figure. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 sides are there. So, 16 * 3. Perimeter is equal to 16 * 3 = 48 cm. So, option C is the answer.
Question number 29. Which of the following figures has an area of 20 square units and a perimeter of 18 units? We will have to find the area and perimeter of all these four figures. So, we will have to find the area and perimeter of all the figures given. So, 1, 2, 3. 1, 2, 3, 4, 5, 6. 6 * 3 = 18 square units. And the perimeter is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. 3, 4, 5, 6, 7, 8. 2 * 9 = 18. 1, 2, 1, 2, 3, 4, 5, 6, 7, 8. 2 * 8 = 16. And 2 + 8 = 10. 20 square units. And perimeter is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. 4 * 5 = 20 square units. And 2 * (4 + 5) = 2 * 9 = 18 units. The option that was asked for, 20 square units and 18 units, is option D.
Option of this chapter. For this, first, we will make a proper figure. Okay. A figure like this. [Music] So, one rectangle will be formed. One will be this. And in between, there is a playground whose area is. Its measurement is 7. And its. Okay. We need to find this portion. Now, C, D, E, F, G, H, I, J. This is some figure. Area of rectangle ABCG. First, we will find the area of this rectangle. 20 * 10 = 200 square meters. 144 square meters. Area of rectangle DEF. We will find the area of this rectangle. [Music] Found. Given 124 square meters = 200 + 144 + 12 - 1112. [Music] 4 square meters.