Solution:
Given the triangle ABC as shown below:
To evaluate angle A,
Step 1: Identify the sides of the triangle ABC.
Thus, using A as the angle of focus,
[tex]\begin{gathered} AB\implies\text{hypotenuse} \\ AC\implies\text{Adjacent} \\ BC\implies\text{Opposite} \end{gathered}[/tex]
Step 2: Write a trigonometric equation to measure A
Using trigonometric ratio,
[tex]\begin{gathered} \tan \text{ A= }\frac{opposite}{Adjacent} \\ =\frac{BC}{AC} \\ \text{where BC=45, AC=28} \\ \text{thus,} \\ \tan \text{ A=}\frac{45}{28} \\ \Rightarrow A=\tan ^{-1}(\frac{45}{28}) \end{gathered}[/tex]
Hence, the trigonometric equation is
[tex]A=\tan ^{-1}(\frac{45}{28})[/tex]
