Pie charts
Pie charts, which show how the parts make up the whole: the whole circle is 100% and the angles at the centre add up to 360°; finding the largest and smallest parts; finding a missing angle; finding the amount in a part, or the total, from angles or percentages; comparing two parts; and a caution: when two pie charts have different totals, comparing percentages alone is not enough. Pupils are not asked to draw pie charts by hand.
Key words
| Chinese | English |
|---|---|
| 圓形圖 | pie chart |
| 扇形 | sector |
| 圓心角 | angle at the centre |
| 百分數 | percentage |
| 全部 | whole |
The 4 short lessons and the chapter test
Lessons are in Chinese for now.
- 認識圓形圖
- 圓心角
- 以百分數標示的圓形圖
- 闡釋圓形圖
- 章節測驗 (chapter test)
Sample questions (in Chinese)
Question 1根據圓形圖（六年級學生最喜愛的運動），哪一項最多？
- 籃球
- 足球
- 游泳
Answer and explanation
答案：A．籃球
為甚麼？扇形越大，數量越多。「籃球」的扇形最大。
Question 2圓形圖顯示小明一天的時間分配。「上學」的扇形的圓心角是多少度？
°
Answer and explanation
答案：90°
為甚麼？各扇形的圓心角合起來是 360°。360° − 180° − 90° = 90°。
Question 3小明一天的時間分配如圓形圖所示，總數是 24 小時。「上學」有多少小時？
小時
Answer and explanation
答案：6 小時
為甚麼？「上學」的圓心角是 90°，佔全部的 90360。24 × 90360 = 6 小時。
Question 4某班學生的上學方法如圓形圖所示，總數是 80 人。「步行」有多少人？
人
Answer and explanation
答案：24 人
為甚麼？80 × 30% = 80 × 30100 = 24 人。
Based on learning unit 6D3 of the Education Bureau’s Primary Mathematics Curriculum (2017).