Answer and Explanation:
The trigonometric ratio cosine is defined as:
[tex]\cos(\theta)=\dfrac{\text{adjacent}}{\text{hypotenuse}}[/tex]
Plugging in the given values for both acute angles:
[tex]\boxed{\cos(R)=\dfrac{28}{53}}[/tex]
[tex]\boxed{\cos(S) = \dfrac{45}{53}}[/tex]
