Answer:
a. 3.5
Step-by-step explanation:
Since ∆ABG is similar to ∆CDG, therefore, their corresponding side lengths are proportional to each other.
Therefore:
DG/BG = GI/GH
10/5 = 7/GH (substitution)
Cross multiply
GH*10 = 7*5
GH*10 = 35
Divide both sides by 10
GH = 35/10
GH = 3.5
