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    Uhm maybe a stupid question...

    Can you use the formula for an area of a non right-angled triangle using radians...

    a= 1/2bh x sin theta

    I have noticed I keep getting the same answer for area of triangle and area of sector the triangle is in. Which obviously is not correct - the formula are more or less the same.
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    (Original post by christinajane)
    Uhm maybe a stupid question...

    Can you use the formula for an area of a non right-angled triangle using radians...

    a= 1/2bh x sin theta

    I have noticed I keep getting the same answer for area of triangle and area of sector the triangle is in. Which obviously is not correct - the formula are more or less the same.
     \displaystyle \text{Area of triangle}\: = \frac{1}{2}ab \sin C C can be in degrees or radians, just make sure your calculator is in the right setting

     \displaystyle \text{Area of sector}\: = \frac{1}{2}\theta r^2

    so an isoceles triangle with a small angle between the two equal length sides will give roughly the same answer in both formula, although the answers are not usually similar

    Edit: could you post an example of a question and your working out
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    (Original post by christinajane)
    Uhm maybe a stupid question...

    Can you use the formula for an area of a non right-angled triangle using radians...

    a= 1/2bh x sin theta

    I have noticed I keep getting the same answer for area of triangle and area of sector the triangle is in. Which obviously is not correct - the formula are more or less the same.
    Do you mean this?



    If so, it should work for any triangle. Could you give me an example of your calculation?
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    https://0e90d90be05fe2865012661b731d...apter%2006.pdf

    Question three in the mixed exercise - page 46 in the above link.

    I may just be reading the question wrong!

    The arc formed by a2 is part of the sector?

    So area of sector is

    A=1/2x17^2 x 2.16
    a=120cm

    So i worked out the area re of the triangle using the enclosed angle in radians using the formula:

    A = 1/2 d x c x sine theta
    a= 1/2 17 X 17 X sin 2.16
    a = 120

    I got the other parts to the question correct so the value for theta is correct.

    I got the correct answer in the end using the formula for the segment.

    So its more just for information/interest purposes!

    I might just be reading the question wrong though....
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    (Original post by christinajane)

    A=1/2x17^2 x 2.16
    a=120cm
    Silly calculation error.

    Try doing that again, A = \frac{1}{2} \times 17^2 \times 2.16 = \frac{1}{2} \times 289 \times 2.16 = 144.5 \times 2.16 = 312.12 \neq 180
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    Argh again!? haha

    I think I am dyslexic....no joke!

    Thank you Zacken.
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    (Original post by christinajane)
    Argh again!? haha

    I think I am dyslexic....no joke!

    Thank you Zacken.
    Not a problem! By the way, when you're replying to someone on here, you should press the "reply" button on their post so that the person receives a notification that you've replied to them!
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    Like this?

    Thank you.
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    (Original post by christinajane)
    Like this?

    Thank you.
    Not quite, it seems you haven't pressed the reply button under my post.

    Not a problem at all!
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    Hahah oh god.

    Like this then?

    Was pressing the one to the right of your post....Is there any hope for me!?

    Have a good day.
 
 
 
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