The topic is Xiao Ming has a rectangular garden. The length of the garden is10m and the width is 6m. He wants to build a path around the garden. The width of the road is 1 m. What is the total perimeter of the whole garden and path after the path is repaired?
Xiaoming's garden is a rectangle, with a length of10m and a width of 6m. He is going to build a path 1 meter wide outside the garden. Our task is to find out the total perimeter of the whole garden and path after repairing the path. To calculate the perimeter, we need to know the formula for calculating the perimeter of a rectangle, that is, perimeter =2× (length+width).
In this topic, we have two rectangles to consider: one is the original garden and the other is the path. The circumference of the original garden is 2× (10+6) = 32m. A path is added to the periphery of the garden, which is equivalent to an increase of 2 meters in length and width on the basis of the original garden. The length of the new rectangle including the path is 12m (10m+2m) and the width is 8m (6m+2m). So the circumference of the new rectangle is: 2× (12+8) = 40m. After the path is repaired, the total perimeter of the whole garden and path is 40 meters.
Calculation method of perimeter of grade three:
1. Calculation of the circumference of a rectangle: The rectangle has two pairs of equal sides, so it is relatively simple to calculate its circumference. Students only need to add up the length and width, and then multiply by 2 to get the circumference of the rectangle. In this way, they can better understand the application of multiplication in real life and cultivate their own computing ability.
2. Calculation of the circumference of a square: The four sides of a square are equal in length, so it is easier to calculate the circumference. Students only need to know the length of one side and then multiply it by 4 to get the circumference of the square. This helps them to better understand the concept of multiple and further improve their computing power.
3. Calculation of the perimeter of irregular graphics: For irregular graphics, students need to measure the length of each side, and then add the lengths of all sides to get the perimeter of the graphics. This helps to cultivate their measurement skills and addition calculation ability, and also enables them to better understand the concept of perimeter. Through a lot of practice, they can easily master these skills and lay a solid foundation for future mathematics learning and practical application.