HELP! If the area of a rectangle is 10x^2+3x-4 and the width is 2x-1, what is the side length of the rectangle?

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since the cosine is the ratio of the adjacent side to the hypotenuse, you can see that cos 60° = ½. answer. according to the property of cofunctions (topic 3), sin 30° is equal to cos 60°. sin 30° = ½.