Answer:
∠B = 60°
a = 4.0 units
b = 6.9 units
Explanation:
The triangle is right angled. The sum of all angles of a triangle is equal to 180 degrees.
The 3 angles are 90, 30 , ∠B .

Thus, B = 180 - 120 = 60 degrees
by trigonometry,
sin(30) =
= 0.5
a = (8)(0.5) = 4 units
Also,
cos(30) =
= 0.866
b = (8)(0.866)= 6.928