If sin A = 5/13. Find cos A, tan A, cosec A, sec A, cot A

 

sin A = 5/13

 

 (side opposite  to  ∠A)/Hypotenuse = 5/13

 ⇒ BC/AC = 5/13

 

Let

      BC = 5x

      AC = 13x

 

We find AB using Pythagoras Theore

Triangle ABC 13x 5x .jpg

 

In Δ ABC, using Pythagoras theorem

(Hypotenuse) 2 = (Height) 2 + (Base) 2

  AC 2 = AB 2 + BC 2

  (13x) 2 = AB 2 + (5x) 2

  169x 2 = AB 2 + 25x 2

  169x 2 – 25x 2 = AB 2

  144x 2 = AB 2

  AB 2 = 144x 2

  AB = √144x 2

  AB = √144 x

  AB = 12x

 

So, our triangle becomes

Finding ratios when other ratios are given - Part 2

 

Now, we find cos A & tan A

Finding ratios when other ratios are given - Part 3

 

Now, let us find cosec, cot and tan

Finding ratios when other ratios are given - Part 4

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.