Both choices (C) and (E) are correct answers to question 59 (page 70) in the Math section of the first practice test in the newly published Official ACT Prep Guide 2016. I have reproduced the entire question along with my video explanation that clarifies this mistake.
Practice Test #1: Question 59 Mathematics
In scalene triangle $\triangle GHI$ shown below, point $J$ lies on side $\overline{HI}$, $\overrightarrow{GJ}$ bisects $\angle HGI$ such that $\angle HGJ$ and $\angle IGJ$ each measure $\theta$, and the given lengths $a$, $b$, $c$, $d$, and $e$ are in inches and are distinct. For all possible values of $\theta$, the area of $\triangle GHJ$ is what fraction of the area of $\triangle GHI$ ?
- $\dfrac{1}{2}$
- $\dfrac{a}{b}$
- $\dfrac{d}{d+e}$
- $\dfrac{ad \sin{\theta}}{b(d+e)\sin{2\theta}}$
- $\dfrac{c \sin{\theta}}{b \sin{2 \theta}}$
Thank you so much! This video was very helpful and easy to follow.