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Question
In ΔABC, ∠B = 90°. If AB = 12units and BC = 5units, find: sinA
Solution
In ΔABC,
AC2 = AB2 + BC2
⇒ AC = `sqrt("AB"^2 + "BC"^2)`
⇒ AC = `sqrt(12^2 + 5^2)`
= `sqrt(144 + 25)`
= 13
AB = 12units
BC = 5units
AC = 13units
sin A
= `"Perpendicular"/"Hypotenuse"`
= `"BC"/"AC"`
= `(5)/(13)`.
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