This is a right angled triangle.
C = 90°, c =19, c =Hypotenuse
A = ?, a = 3
By Pythagoras' Theorem:
a² + b² = c²
3² + b² = 19²
9 + b² = 361
b² = 361 - 9
b² = 352
b = √352
b ≈ 18.76
Using Sine A = Opposite / Hypotenuse
Sin A = 3/19 ≈ 0.1579
A =Sin⁻¹(0.1579)
A ≈ 9.09°
Sum of angles in a triangle =180
A + B + C = 180
9.09 + B + 90 =180
B + 99.09 =180
B =180 - 99.09
B = 80.91
A ≈ 9.09°, B ≈ 80.91°, b ≈ 18.76
Hope this helps.
