First, please go to the following website and see the figure (picture). Then, please help me to answer the two questions.
Figure website: http://www.geocities.jp/sms12147/math.JPG
1) If its area is 54 m^2, find the value of x.
2) If a piece of chalk can paint an area of 0.3 m^2 and the value of x in the figure is 12, how many pieces of chalk are needed to paint the whole figure ?
Areas of a simple figure
2007-01-24 5:35 am
回答 (2)
2007-01-24 6:02 am
✔ 最佳答案
1)x=6mtotal area - two triangle at the side = trapezius梯形
54m^2 - (8*3/2) - (4*3/2) = trapezius梯形 = 36m^2
trapezius梯形 area = [(8+4)*x] / 2
x = 36 - [(8+4)*x] / 2 = 6
2）x=90
total area / 0.3m^2
total area = (8*3/2) + (4*3/2) + [12*(8+4)] / 2 = 18 + 72 = 90
2007-01-23 22:04:17 補充：
trapezium*2) not yet finish90/0.3 =300300chalks are needed
2007-01-24 5:46 am
area of ⊿ABE + area of ⊿DFC + area of trapezium =54
(3)(8)/2 + (3)(4)/2 + (4+8)x/2 =54
12+6+6x=54
6x=36
x=6
2007-01-23 21:49:15 補充：
2)(area of ⊿ABE + area of ⊿DFC + area of trapezium)/0.3[(3)(8)/2 + (3)(4)/2 + (4+8)12/2]/0.3=(12+6+72)/0.3=90/0.3=300枝
(3)(8)/2 + (3)(4)/2 + (4+8)x/2 =54
12+6+6x=54
6x=36
x=6
2007-01-23 21:49:15 補充：
2)(area of ⊿ABE + area of ⊿DFC + area of trapezium)/0.3[(3)(8)/2 + (3)(4)/2 + (4+8)12/2]/0.3=(12+6+72)/0.3=90/0.3=300枝
參考: king
收錄日期: 2021-04-12 23:19:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070123000051KK04357