Answer: 
=========================================================
Explanation:
Use the pythagorean trig identity
and plug in the fact that 
Isolating sine leads to
. I'm skipping the steps here, but let me know if you need to see them.
The result is negative because we're in quadrant 4, when y < 0 so it's when sine is negative.
Therefore,

Answer: 7
Step-by-step explanation:
Answer:
24
Step-by-step explanation:
6.21+6.21=5.7+5.7=23.82
23.82 rounds to 24
(perimeter is all of the sides combined)
Answer:
9.625 gallons will be used by the painters in 3.5 hours
Step-by-step explanation:
2.75 gallons = 1 hr
X gallons = 3.5 hrs
X = (3.5 × 2.75)/1
X = 9.625 gallons
9.625 gallons will be used by the painters in 3.5 hours