Answer:
Jada used 1/2 of the pancake mix in the box
Step-by-step explanation:
we know that
-----> represent the 100% of the box
so
by proportion
Find what fraction represent 
First convert mixed number to an improper fraction

Convert the percentage into fraction

Answer:
Segment DE is half the length of segment AC. -- Substitution property of equality
Step-by-step explanation:
Here is given a proof for proving line joining mid segment is parallel and half the length of third side.
Stepwise proof is given in two columns
We find that for every line there is a justification as
STatement Justification
D and E coordinates found out MId point formula
DE and BC are measured Distance formula
DE=1/2 BC Substitution property of equality
This justification was missing in the given proof and with this included proof would be complete
ANSWER
M=(−3,72)
Find A midpoint calculator on the internet