5. The Sine and Cosine Ratios
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The cosine of an acute angle is equal to the sine of its complement.
sin 17^(∘)
The cosine of an acute angle is equal to the sine of its complement. |
Keep in mind that complementary angles add up to 90^(∘). To find the complement of 73, we subtract our given angle from 90. Now, we can rewrite cos 73^(∘) in terms of sine. cos 73^(∘) = sin(90^(∘)-73^(∘)) = sin 17^(∘)