Is y=4 and x=8 perpendicular ??

yes

Step-by-step explanation:

y=4 is a horizontal line which crosses the y-axis at 4; slope is zero

x=8 is a vertical line which crosses the x-axis at 8; slope is undefined

v: l•w•h÷2.

v: 20•6•8 ÷2

v: 960÷2

v: 480

b.) 160 miles on a 5 gallons car

step-by-step explanation:

240/10=24 miles/gallon

160/5=32 miles/gallon

30/1=30 miles/gallon

168/6= 28 miles/gallon

32 miles/gallon is the most amount, so this is the best.