Can anyone explain how to do this? The answer isn't as important as the explanation. My teacher gave us a video w/o an example like this so I don't know what to do lol

Answer:
x = 182.53
Step-by-step explanation:
Use trigonometric ratios to find the whole side length (a) adjacent to 20° and the side length (b) adjacent to 57° respectively. Then find the difference. That would give you the value of x. That is: a - b = x
Let's solve.
✍️Finding the whole side length adjacent to 20°:
Opp = 87
Adjacent length = ? = a
[tex] \theta = 20 [/tex]
Thus,
[tex] tan(\theta) = \frac{opposite}{adjacent} [/tex]
Plug in the values
[tex] tan(20) = \frac{87}{a} [/tex]
Multiply both sides by a
[tex] tan(20) \times a = \frac{87}{a} \times a [/tex]
[tex] tan(20) \times a = 87 [/tex]
Divide both sides by tan(20)
[tex] \frac{tan(20) \times a}{tan(20)} = \frac{87}{tan(20)} [/tex]
[tex] a = \frac{87}{tan(20)} [/tex]
[tex] a = 239.03 [/tex]
Finding the side length adjacent to 57°:
Opp = 87
Adjacent length = ? = b
[tex] \theta = 57 [/tex]
Thus,
[tex] tan(\theta) = \frac{opposite}{adjacent} [/tex]
Plug in the values
[tex] tan(57) = \frac{87}{b} [/tex]
Multiply both sides by b
[tex] tan(57) \times b = \frac{87}{b} \times b [/tex]
[tex] tan(57) \times b = 87 [/tex]
Divide both sides by tan(57)
[tex] \frac{tan(57) \times b}{tan(57)} = \frac{87}{tan(57)} [/tex]
[tex] b = \frac{87}{tan(57)} [/tex]
[tex] b = 56.50 [/tex]
Therefore:
x = a - b
x = 239.03 - 56.50
x = 182.53