Answer:
The correct answer AC = 11.52
Explanation:
From the figure attached with this answer shows the triangle ABC.
BC=4 centimeters, m angle B=m angle c, and m angle a = 20 degrees
To find AC
From the figure we can see that D is the mid point and AD⊥BC
Then BD = CD = 4/2 = 2 cm
<BAD = 10° and <CAD = 10°
By using trigonometric ratio,
sin 10 = CD/AC = 2/AC
AC = 2/sin 10 = 2/0.1736 = 11.52
Therefore the value of AC = 11.52 cm