In a right triangle sin A=0.8 what’s is the decimal value of cos A ?

1 Answer
May 2, 2018

#cosA=0.6#

Explanation:

one method is to use the identity

#sin^2x+cos^2x=1#

#sinA=0.8#

#0.8^2+cos^2A=1#

#cos^2A=1-0.8^2#

#cos^2A=#1-0.64#

#cos^2A=0.36#

#cosA=sqrt0.36=0.6#

since we have a right angled triangle

#"angle" A <90^0=>cosA>0#