Unit 5 Polygons in life - the area of polygons 五 生活中的多边形——多边形的面积 Schematic diagram of glass 玻璃示意图 Length: 1.2 m Height: 0.7 m 长：1.2米 高：0.7米 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 How many square meters is the area of this glass？ 1. 这块玻璃的面积是多少平方米？ The shape of glass is a parallelogram. 玻璃的形状是平行四边形。 How do you find the area of a parallelogram? 怎样求平行四边形的面积呢？
So let's verify that. 我们来验证一下吧。 What is the relationship between the assembled rectangle and the original parallelogram? 拼成的长方形与原来的平行四边形之间有怎样的关系？ The area of the parallelogram = base × height 平行四边形的面积＝底×高 It is expressed by letters: S = Ah 用字母表示：S＝ah Glass area: 1.2×0.7 = 0.84(square meter) 玻璃的面积： 1.2×0.7＝0.84(平方米) Answer: the area of this glass is 0.84 square metre. 答：这块玻璃的面积是0.84平方米。
Lesson 2 Schematic diagram of the sign 标志牌示意图 Length: 9 dm Height: 7.8 dm 长：9分米 高：7.8分米 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 1. How many square decimeters of aluminum leather are needed to make this sign? 1. 制作这个标志牌需要多少平方分米的铝皮？ The sign is triangular. 标志牌是三角形的。 How do we figure out the area of a triangle? 怎样求三角形的面积呢？ The calculation formula of the area of the parallelogram is derived by transforming the parallelogram into a square. How about the triangle? 平行四边形的面积计算公式是把平行四边形转化成长方形推导出来的，三角形呢？ What is the relationship between the parallelogram and the original triangle? 拼成的平行四边形与原来的三角形之间有怎样的关系？ The area of a triangle = base × height ÷2 三角形的面积＝底×高÷2 It is expressed by letters: S = ah ÷2 用字母表示：S＝ah÷2 Area of the sign: 9×7.8÷2 = 35.1(decimeter square) 标志牌的面积：9×7.8÷2＝35.1(平方分米) Answer: It took 35.1 decimeters of aluminum to make the sign. 答：制作这个标志牌需要35.1平方分米的铝皮。
Lesson 3 Plane Diagram of Chair 椅子平面示意图 Upper base: 32cm Lower base: 36cm Height: 32cm 上底： 32厘米 下底：36厘米 高：32厘米 What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 1. How many square centimeters of wood is needed to make the chair top? 1. 制作这个椅子面需要多少平方厘米的木材？ The face of the chair is trapezoidal. How do you figure out the area of a trapezoid? 椅子的面是梯形的。怎样求梯形的面积呢？ We can study it with the help of tools. 我们可以借助学具来研究。 Use two identical trapezoids to form a parallelogram. 用两个完全一样的梯形拼成一个平行四边形。 What is the relationship between the assembled parallelogram and the original trapezoid? 拼成的平行四边形与原来的梯形之间有怎样的关系？ Area of trapezoid = (upper base + lower base)× height ÷2 梯形的面积＝(上底＋下底)×高÷2 It is expressed by letters:：(a＋b)×h÷2 用字母表示：(a＋b)×h÷2 The area of the chair :(32+36)×32÷2 = 1088(square centimetres) 椅子的面积是：(32＋36)×32÷2＝1088(平方厘米) Answer: 1088 square centimeters of wood is needed to make this chair surface. 答：制作这个椅子面需要1088平方厘米的木材。
Lesson 4 Diagram of Shrimp Pond 虾池示意图 What is the area of the shrimp pond ? 虾池的面积是多少平方米？ What questions can you ask? 你能提出什么问题？ Cooperative exploration 合作探索 How many square meters is the area of the shrimp pond? 1. 虾池的面积是多少平方米？ Can you figure out the area of the figure below? 你会求下面图形的面积吗？ Related links 相关链接 How big the new school is! 新建的学校好大呀! The school covers an area of 4 hectares. 学校占地4公顷。 How big is a hectare? 1. 1 公顷有多大？ The sides are 100 meters square and the area is 1 hectare. 边长是100米的正方形，面积是1公顷。 100 times 100 equals to 10000(m2) 100×100＝10000(平方米) 10000 square meters = 1 hectare 10000平方米＝1公顷 The size of my house is about 100 square meters, and 100 units of such houses are about 1 hectare. 我家的住房面积大约有100平方米，100套这样的住房面积大约是1公顷。 Is there a unit of area larger than a hectare? 还有比公顷更大的面积单位吗？ The area of a square with sides of 1000 meters is 1 square kilometer, 1 square kilometer can be written as 1k square meters, 1 square kilometer = 100 hectares. 边长1000米的正方形的面积是1平方千米，1平方千米可以写成1k㎡, 1 平方千米＝100公顷。 Land area is usually measured in hectares and square kilometers. 测量土地面积时，常用公顷和平方千米作单位。 Pay attention to our living space 关注我们的生活空间 Raise a question 提出问题 The runway is too short. When can our school build a big playground too! 跑道太短了。什么时候我们学校也能修建一个大操场呀！ There are more and more students in our school. What about the conditions of the playground? 我们学校的学生越来越多，活动场地状况怎样呢？ Launch an investigation 展开调查 We will investigate the requirement of activity ground about pupil! 我们来调查一下有关小学生活动场地的要求吧! Our activity venues include all kinds of classrooms, halls, corridors, space outside the building, playground... 我们的活动场地包括各种教室、楼内大厅、走廊、楼外空地、操场…… Actual measurement 实际测量 Does our school's floor space per student meet the standard? Measure it! 我们学校的生均占地面积达到标准了吗？测量一下吧！ I guess the length of the playground is... 我估计操场的长是…… My step length is about 0.6 meters. 我每步长大约是0.6米。
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