He used 7 pints all together because there at 2 cups in each pint and 4 pints in a half a gallon.
Tape diagrams are simple. Look at the picture I put in the comments
400 x .75 = 300
300 x .10 = 30
300 + 30 = 330
The final coat of the GoPro is 330!
Answer:

Step-by-step explanation:
On the right side of the = multiply -4 through

add 28a and add 4 to both sides


divide both sides by 22

Perpendicular is the answer because for it to be perpendicular it has to be the opposite 3/4’s opposite is -4/3 which is why the answer is perpendicular