Question

What is the correct value of b ?

Answer 1

Answer:

b = 4

Step-by-step explanation:

Using the trigonometric identity

cos x = $\frac{1}{secx}$ = $\frac{1}{\frac{5}{3} }$ = $\frac{3}{5}$

Using the cosine ratio in the right triangle

cos x = $\frac{adjacent}{hypotenuse}$ = $\frac{3b}{20}$

Hence

$\frac{3b}{20}$ = $\frac{3}{5}$ ( cross- multiply )

15b = 60 ( divide both sides by 15 )

b = 4