If sin 3A = cos (A – $10^\circ$) and 3A is acute then A =?

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KollegeApply · Accepted Answer

$25^\circ$ Explanation: sin 3A = cos (A – $10^\circ$) $\Rightarrow$ cos ($90^\circ$ – 3A) = cos (A – $10^\circ$) $\Rightarrow$ $90^\circ$ – 3A = A – $10^\circ$ $\Rightarrow$ 4A = $100^\circ$ $\Rightarrow$ A = $25^\circ$

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