Answer:
[tex] b = 5 \sqrt{3} [/tex]
Step-by-step explanation:
For the 30-deg angle, 5 is the opposite leg.
b is the adjacent leg.
The trig ratio that relates the opposite leg to the adjacent leg is the tangent.
[tex] \tan A = \dfrac{opp}{adj} [/tex]
[tex] \tan 30^\circ = \dfrac{5}{b} [/tex]
[tex] b \tan 30^\circ = 5 [/tex]
[tex] b = \dfrac{5}{\tan 30^\circ} [/tex]
[tex] b = \dfrac{5}{\frac{\sqrt{3}}{3}} [/tex]
[tex] b = \dfrac{15}{\sqrt{3}} [/tex]
[tex] b = \dfrac{15 \sqrt{3}}{\sqrt{3} \sqrt{3}} [/tex]
[tex] b = \dfrac{15 \sqrt{3}}{3} [/tex]
[tex] b = 5 \sqrt{3} [/tex]