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In right angle triangle ABC 15 cm and 17 cm are the lengths of AB AND AC respectively. Then find out all the six trigonometric ratios of angle A​

Answer»

Question :-

In a right angled TRIANGLE ABC , ∠B = 90° . 15 cm & 17cm are the length of the sides AB and AC . we need to find out all the six trigonometric ratios of angle A ?

Answer :-

Given :-

In a right angled triangle ABC , ∠B = 90°

AB = 15 cm , AC = 17 cm

Required to find :-

  • All the six trigonometric ratios of angle A ?

Diagram :-

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Solution :-

Given :-

In right angled triangle ABC ;

∠B = 90° , AB = 15 cm , AC = 17 cm

we need to find the all six trigonometric ratios of angle A .

So,

In order to find all the six trigonometric ratios .

FIRST let's find the unknown side .

Using the PYTHAGOREAN THEOREM ;

\\  \tt{AB^2 + BC^2 = AC^2  }  \\ \\  \rm( \because AB = 15  \: cm , AC = 17 \:  cm  ) \\  \\  \tt (15 {)}^{2}  + (BC {)}^{2}  = (17 {)}^{2}  \\  \\  \tt 225 +  {BC}^{2}  = 289 \\  \\  \tt  {BC}^{2}  = 289 - 225 \\  \\  \tt  {BC}^{2}  = 64 \\  \\  \tt  BC  =  \sqrt{64} \\  \\  \tt  BC = \pm 8 \: cm \:  \\  \\  \sf \because Length  \: can \: 't be \:  in \:  negative  \\  \\  \rm \implies \: BC = 8 \: cm

Now,

Let's find the all trigonometric ratios of angle A .

So,

We know that ;

1st trigonometric ratio :-

\boxed{\rm{\red{ \sin \theta = \dfrac{ Opposite \; \; side }{ Hypotenuse } }}}

( Note :- Here \theta = A )

So,

Sin A = Opposite side / Hypotenuse

Sin A = BC/AC

Sin A = 8/17

Hence,

Sin A = 8/17

Now,

2nd trigonometric ratio :-

\boxed{\rm{ \red{ \cos \theta =  \dfrac{Adjacent \:  \:  side}{ Hypotenuse}}}}

So,

Cos A = Adjacent side / Hypotenuse

cos A = AB/AC

cos A = 15/17

Hence,

cos A = 15/17

Now,

3rd trigonometric ratio :-

\boxed{ \rm{ \red{ \tan \theta = \dfrac{Opposite \;  \: side }{Adjacent \;  \: side }}}}

So,

Tan A = opposite side/ Adjacent side

Tan A = BC/AB

Tan A = 8/15

Hence,

Tan A = 8/15

Now,

4th trigonometric ratio :-

\boxed{  \rm{ \red{ \cosec \theta =  \dfrac{ Hypotenuse}{Opposite  \:  \: side}}}}

so,

Cosec A = Hypotenuse/Opposite side

Cosec A = AC/AB

Cosec A = 17/8

Hence,

Cosec A = 17/8

Now,

5th trigonometric ratio :-

\boxed{ \rm{ \red{ \sec \theta =  \dfrac{ Hypotenuse}{Adjacent \:  \:  side}}}}

So,

Cosec A = Hypotenuse/ Adjacent side

Cosec A = AC/AB

Cosec A = 17/15

Hence,

Cosec A = 17/15

Now,

6th trigonometric ratio :-

\: \boxed{  \rm{ \red{ \cot \theta = \dfrac{Adjacent \;  \: side }{Opposite \;  \: side }}}}

So,

cot A = Adjacent side/ Opposite side

cot A = AB/BC

cot A = 15/8

Hence,

cot A = 15/8

\huge{\sf{\pink{\checkmark{ Hence \; solved }}}}



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