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 Algebra Pre-Algebra and Basic Algebra Math Forum

March 2nd, 2013, 06:08 PM   #1
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Find all the sides of this triangle.

[attachment=0:1rwvoeut]untitled5.JPG[/attachment:1rwvoeut]
CQ=6cm,QB=8cm
Find all other sides of the triangle.

If you have solution or progress PM me or hide it here someway....
I am testing the approach of different people....
Attached Images untitled5.JPG (30.6 KB, 233 views) March 2nd, 2013, 06:55 PM #2 Global Moderator   Joined: May 2007 Posts: 6,834 Thanks: 733 Re: Find all the sides of this triangle. They depend on the radius, which hasn't been given. March 2nd, 2013, 06:58 PM #3 Senior Member   Joined: Dec 2012 Posts: 450 Thanks: 0 Re: Find all the sides of this triangle. Oh sorry, I forgot it. Ok the radius is 4cm.... March 2nd, 2013, 09:42 PM #4 Global Moderator   Joined: Dec 2006 Posts: 21,019 Thanks: 2254 Use the first formula given here. March 3rd, 2013, 02:08 PM #5 Senior Member   Joined: Sep 2010 Posts: 221 Thanks: 20 Re: Find all the sides of this triangle. The sides are AC=18; AB=20. I can post a solution if needed. March 3rd, 2013, 03:53 PM #6 Senior Member   Joined: Dec 2012 Posts: 450 Thanks: 0 Re: Find all the sides of this triangle. Ok,post it then.... Sorry,no,no PM me.....Let me see your approach. March 4th, 2013, 12:56 AM #7 Global Moderator   Joined: Dec 2006 Posts: 21,019 Thanks: 2254 McPogor slipped up. March 4th, 2013, 07:01 AM #8 Senior Member   Joined: Sep 2010 Posts: 221 Thanks: 20 Re: Find all the sides of this triangle. Here's succession of steps. 1)CQ=CR=6; QB=BP=8; AR=AP=x. 2)OC=Sqrt[QC^2+OQ^2]=Sqrt{36+16]=2Sqrt13 OB=Sqrt[QB^2+OQ^2]=Sqrt[64+16]=4Sqrt5. 3)Sin(C/2)=OQ/OC=2/Sqrt13; Sin(B/2)=OQ/OB=1/Sqrt5. 4)Cos(C/2)=Sqrt[1-sin^2(C/2)]=3Sqrt(1/13); Cos(B/2)=Sqrt[1-Sin^2(B/2)]=2Sqrt(1/5). 5)SinC=2Sin(C/2)Cos(C/2)=12/13; SinB=2Sin(B/2)Cos(B/2)=4/5. 6)AC/SinB=AB/SinC; (6+x)/(4/5)=(8+x)/(12/13). 5(6+x)=13(8+x)/3. Eventually x=12. AC=6+12=18; AB=8+12=20. March 4th, 2013, 07:40 AM   #9
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Quote:
 Originally Posted by McPogor Eventually x=12.
Incorrect. You omitted the working at precisely the point where you slipped up. March 4th, 2013, 10:16 AM #10 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038 Re: Find all the sides of this triangle. triangle sides 14-18-20 has area 122.376.... your triangles AOC + AOB + BOC = 36 + 40 + 28 = 104 Sooooo...................listen to Skip If AC = b, then triangle ABC has sides 14, b and b+2 Tags find, sides, triangle Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post adilgrt007 Algebra 9 August 22nd, 2013 10:25 AM Britwells Algebra 3 March 27th, 2013 01:31 PM mathmaniac Algebra 16 February 14th, 2013 06:27 PM MathMathHelloMath Algebra 3 October 13th, 2010 03:42 PM MathMathHelloMath Calculus 1 October 13th, 2010 06:06 AM

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