Hi, again!
First blank: multiplication property of equality
Both sides of the equation were multiplied by (1/2).
Second blank: m<E
Angle E is an inscribed angle intercepting arc FGD, so by the inscribed angle theorem, its measure is half the measure of the arc.
Third blank: m<G
Same explanation as the prior blank
Fourth blank: substitution property of equality
Since angle E is equal to half the measure of arc FGD, we can replace that term. Likewise with angle G.