Given a right triangle ABC with angle C as 90 degrees, find angle A if side AC = 3.0 units and BC = 6.8 units and AC = 3.0 units, find angle A.

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How do i get the answer for 2/3 * 10/3

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?