If sin angle A= 4/5 , then what does cos angle A equal? cos angle A= 5/8; cos angle A= 1/2; cos angle A= 4/5; cos angle A= 3/5

Question

asked Jan 9, 2024 176k views

1 Answer

Oliver Keyes · Answer 1 · 2024-01-16T02:55:06+0000

Note :- Kindly see Attached Pic

★ By using Phythagoras theorem:-

$\sf \longrightarrow \: {AC }^(2) = {BC}^(2) + {AB}^(2) \\$

$\sf \longrightarrow \: {5 }^(2) = {4}^(2) + {AB}^(2) \\$

$\sf \longrightarrow \: {4}^(2) + {AB}^(2) = {5}^(2) \\$

$\sf \longrightarrow \: 16 + {AB}^(2) = 25 \\$

$\sf \longrightarrow \: {AB}^(2) = 25 - 16 \\$

$\sf \longrightarrow \: {AB}^(2) = 9 \\$

$\sf \longrightarrow \: AB = √(9) \\$

$\sf \longrightarrow \: AB = 3 \\$

★ Cos A :-

$\sf \leadsto \: Cos A = (AB)/( AC) \\$

$\sf \leadsto \: Cos A = (3)/( 5) \\$

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