Answer:
s = 13.6
m∠T = 35.7°
m∠U = 61.3°
Explanation:
• Solving for side s:
To find the length of side s, we have to use the cosine rule:
,
where:
- a = unknown side
- b, c = adjacent sides
- A = angle opposite to the unknown side.
In this case, the unknown side is s, and the sides adjacent to it have lengths of 8 and 2. The angle opposite to s is ∠S = 83°. Therefore,

⇒
⇒

• Solving for m∠T:
In order to find m∠T, we can use the sine rule:
,
which means that the ratios of the sines of angles and their opposite sides are equal for a triangle.
The side opposite to ∠T is US = 8. Therefore:

⇒

⇒

⇒

• Solving for m∠U:
Now that we know the values of two angles of the triangle, we can calculate the third angle using the fact that the angles in a triangle add up to 180°:
∠U + ∠S ∠T = 180°
⇒ ∠U + 83° + 35.7° = 180°
⇒ ∠U = 180° - 83° - 35.7°
⇒ ∠U = 61.3°