Question

If `sin A = 3/5`, what is `sec A`?

Answer 1

Let `{(mathbf{A} ... "Adjacent"),(mathbf{H} ... "Hypotenuse"),(mathbf{O} ... "Opposite"):}`

Given:
`sin A=3/5={mathbf{O}}/{mathbf{H}} => " Let " {(mathbf{O}=3),(mathbf{H}=5):}`

By Pythagorean Theorem,

`mathbf{A}=sqrt{mathbf{H}^2-mathbf{O}^2}=sqrt{5^2-3^2}=sqrt{16}=4`

Hence,

`sec A=mathbf{H}/mathbf{A}=5/4`

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I hope that this was helpful.