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November 23rd, 2013, 08:59 AM   #1
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Issues finding Triangle Area

Points of vertices for a right angle triangle are : S (-2,2), T(10, -2), R(4, 4)

Here is what I did. I found the length of ST, and RT

I drew a line indicating the height of the triangle from the base to R

Used Pythagorean to get value of h- which is 5.5 I believe

B x H / 2 for Area = 6.3 * 5 / 2

= 17.325 which is indicated as wrong. Can anyone simply explain why please? Thanks
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November 23rd, 2013, 09:00 AM   #2
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Re: Issues finding Triangle Area

By the way length of ST = 6.3, RT = 6.4
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November 23rd, 2013, 09:43 AM   #3
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The points R, S and T that you have given correspond to an obtuse-angled triangle, not a right-angled triangle.
Also, your arithmetic is incorrect.

If you want the area of triangle RST anyway, I suggest you let U be the point (4, 0), which is the mid-point of ST, then find the (equal) areas of isosceles triangle SRU and triangle TRU, using RU as the base in each case, and add the results to get the area of triangle RST.
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November 23rd, 2013, 09:46 AM   #4
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Re: Issues finding Triangle Area

Your length calculations are not correct; how did you get ST = 6.3? Should be SQRT(160).
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