http://i111.photobucket.com/albums/n...v_k/img001.jpg

Figure 1 shows the triangle ABC, with AB=6cm, BC=4cm and CA=5cm

a) show that cosA=3/4

b) hence, or otherwise, find the exact value of sinA

thx!

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- Apr 6th 2008, 08:38 AMkls7162triangle trigonometry
http://i111.photobucket.com/albums/n...v_k/img001.jpg

Figure 1 shows the triangle ABC, with AB=6cm, BC=4cm and CA=5cm

a) show that cosA=3/4

b) hence, or otherwise, find the exact value of sinA

thx! - Apr 6th 2008, 08:45 AMMathstud28here is how I would do this
imput correct values and solve for ...and for the second one use the law of sines which says that where caps are angles and lower case are sides