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# Can someone please explain to me how to do part (b) on this radian question?

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1. Attachment 525277525279
I've done part (a), I'm just not sure what it's really wanting me to do with part (b). I've included the mark scheme too
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2. If cosA = 3/4 this means the adjacent/hypotenuse = 3/4

Adjacent = 3, Hypotenuse = 4
Use the Pythagoras theorem to find the other side of the triangle which is:
4² - 3² = X²
Therefore X = √ 7
sinA = (√ 7)/4
since sinA = opposite / hypotenuse, and we just calculated that the opposite side is √ 7

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