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November 23rd, 2013, 08:59 AM  #1 
Newbie Joined: Oct 2013 Posts: 4 Thanks: 0  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 
November 23rd, 2013, 09:00 AM  #2 
Newbie Joined: Oct 2013 Posts: 4 Thanks: 0  Re: Issues finding Triangle Area
By the way length of ST = 6.3, RT = 6.4

November 23rd, 2013, 09:43 AM  #3 
Global Moderator Joined: Dec 2006 Posts: 20,931 Thanks: 2207 
The points R, S and T that you have given correspond to an obtuseangled triangle, not a rightangled 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 midpoint 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. 
November 23rd, 2013, 09:46 AM  #4 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038  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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