Answer:
1. EF ≈ 22.00
2. m∠E ≈ 36.20°
3. m∠F ≈ 53.81°
Explanation:
1. Use the trigonometric function sine.
sin(60°) = EF / 25.4
EF = 25.4 sin(60°)
EF ≈ 22.00
2. Use the inverse of the trigonometric function sine (denoted arcsin).
sin(m∠E) = 15/25.4
m∠E = arcsin(15/25.4)
m∠E ≈ 36.20°
3. Use the inverse of the trigonometric function cosine (denoted arccos).
cos(m∠F) = 15/25.4
m∠F = arccos(15/25.4)
m∠F ≈ 53.81°