Question

if Sin A is equals to 3 by 4 find cos A angled at b​

Answer 1

cos²A = 1- Sin²A

= 1-(3/4)²

= 1-9/16

cosA =√7/16

Answer 2

$\sin( \alpha ) = 3 \div 4 = p \div h \\ p = 3 \: and \: h = 4 \\ therefore \: b = \sqrt{16 - 9 } = \sqrt{7} \\ \\ hence \: \cos( \alpha ) =b/h= \sqrt{7} \div 4$