數學sin cos tan問題一問
2007-07-22 11:03 pm
The area of a parallelogram is 80cm2. Two of the sides are of lengths 6cm and 15cm. Find the angles of the parallelogram.
回答 (2)
2007-07-22 11:26 pm
✔ 最佳答案
The //gram can be divided into two identical triangle.So its area
= 2 x 1/2 ab sin theta
=ab sin theta
So,
80 = 6 x 15 x sin theta
sin theta = 8/9
theta = 62.73 degree or 117.27 degree. (corr. to 2 d. p.)
2007-07-23 9:14 am
We take 15 cm as the length, then the height of the parallelogram is 80/15 = 16/3 cm (or 5.333 cm). Let x be the acute angle between the 2 sides, then
sin x = (16/3) / 6 = 16/18 = 8/9 => x = 1.0949 radians = 62.734 degrees. The other angle will be PI - 1.0949 = 2.0467 radians = 117.266 degrees.
sin x = (16/3) / 6 = 16/18 = 8/9 => x = 1.0949 radians = 62.734 degrees. The other angle will be PI - 1.0949 = 2.0467 radians = 117.266 degrees.
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