Please help me!!!!!!!

Answer:
b = 11[tex]\frac{1}{4}[/tex] (or 11.25)
Step-by-step explanation:
From the diagram,
b = 15 - a
Since the triangles in the figure are all right angled, apply the appropriate trigonometric function to first determine x. We have;
Sin θ = [tex]\frac{opposite}{hypotenuse}[/tex]
Sin 30 = [tex]\frac{x}{15}[/tex]
x = Sin 30 x 15
= 7.5
x = 7.5
To determine a,
Cos θ = [tex]\frac{adjacent}{hypotenuse}[/tex]
Cos 60 = [tex]\frac{a}{7.5}[/tex]
a = cos 60 x 7.5
= 3.75
a = 3.8
b = 15 - 3.75
= 11.25
b = 11[tex]\frac{1}{4}[/tex]