An angle measuring 870 n degrees is in standard position. For which value of n will the terminal side fall on the y -axis?

For the terminal side to lie on the y-axis, the angle must be a multiple of 90°. With n = 3, the angle is 870 × 3 = 2610°, and 2610° = 28 × 90° + 90°, so its terminal side lies on the positive y-axis. Thus, the correct choice is n is equal to 3.

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