香港介紹ppt

標題:

數學Trigonometric Ratios

• 廣州獵德市污水處理廠資料(急！)
• 請問這句法文的意思是-
• 中文翻譯英文

 

此文章來自奇摩知識+如有不便請留言告知

發問:

ABC is a sector. Its radius is 10cm and the angle at the centre is 70 degree. D is a point on AC such that BD is perpendicular to AC. (a) Find the area of triangle ABD (b) Find the area of the shaded region. Must list full steps and the answers must correct.

最佳解答:

ABC is a sector. Its radius is 10cm and the angle at the centre is 70 degree. D is a point on AC such that BD is perpendicular to AC. (a) Find the area of triangle ABD A. cos 70deg = AD/10 AD = 10 cos 70deg cm sin 70deg = BD/10 BD = 10 sin 70deg cm area of triangle ABD = (10 cos 70deg)(10 sin 70deg)/2 = 16.070cm^2(cor. to 3 d.p.) (b) Find the area of the shaded region. A. I guess the answer is (the area of sector) – (the area of the triangle) area of the shaded region = pi(10)^2(70deg/360deg)- (10 cos 70deg)(10 sin 70deg)/2 = 45.017cm^2(cor. to 3 d.p.) (PS: deg stands for degree because Yahoo cannot show the degree symbol.) If I have made a mistake, please tell me. 2010-05-22 00:28:12 補充： BTW, please provide the diagram next time. Otherwise, no one will understand the question.

其他解答:

Can you provide the diagram??