# Chapter 2 - Review Exercises - Page 94: 12

In letter D, the angle $140^{\circ}$ has no reference angle that is a special angle.

#### Work Step by Step

All the trigonometric functions in A, B, and C can be solved using reference angles that are special. ($30^{\circ}, 45^{\circ}, 60^{\circ}, 90^{\circ}$) But, in letter D, the angle $140^{\circ}$ has no reference angle that is a special angle.

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