A proportion looks like this:
It means that the quantity a,b,c and d are in the same proportion: the ratio between a and b is the same ratio between c and d.
They are particularly useful in situation when you have an example given, and you want to extrapolate the relationship for another couple.
For example, you can think of the following problem: "Five apples cost 2 dollars. How much will 8 apples cost?"
You can build the proportion
And then solve it for x:
Answer:
y = 7.50 + 1.50x
Step-by-step explanation:
The admission costs $7.50 and after x hours Jon has to pay $1.50*x. Then the cost y in dollars is
y = 7.50 + 1.50x where x is the number of hours.
Answer:
none of them
Step-by-step explanation:
Two lines are perpendicular when satisfy the next equation: m1*m2 = -1, where m1 and m2 are the slopes o the lines.
line 1:
y – 1 = (x+2)
y = x + 3
slope of line 1 = 1
line 2:
y + 2 = –3(x – 4)
y + 2 =
-3*x + 12
y = -3*x + 10
slope of line 2 = -3
m1*m2 = 1*(-3
) = -3
They are not perpendicular
line 3:
y − 5 = 3(x + 11)
y − 5 = 3*x + 33
y = 3*x + 38
slope of line 3 = 3
m1*m3 = 1*3 = 3
They are not perpendicular
line 4:
y = -3x –
slope of line 4 = -3
m1*m4 = 1*(-3
) = -3
They are not perpendicular
line 5:
y = x – 2
slope of line 5 = 1
m1*m5 = 1*1 = 1
They are not perpendicular
line 6:
3x + y = 7
y = -3x + 7
slope of line 6 = -3
m1*m6 = 1*(-3
) = -3
They are not perpendicular
