Answer:
a. The equation is y = 19 x
b. The height of 13 DVD cases is 247 mm
Step-by-step explanation:
- A proportional relationship is about two quantities vary directly with
each other
- Ex: If y proportion to x, then y is varies directly with x
That means y ∝ x ⇒ y = k x, where k is the constant of variation
- The height of a stack of DVD case is proportional to the number of
case in the stack
- That means the height of DVD cases varies with the number of cases
- The height of 6 DVD case is 114 mm
a.
∵ The number of cases = x
∵ The height of the cases = y
∴ y ∝ x
∴ y = k x
- To find k lets use the first information above
∵ y = 114 mm when x = 6
- Substitute these values in the equation above to find k
∵ 114 = 6 k
- Divide both sides by 6
∴ k = 19
- Substitute the value of k in the equation above
∴ y = 19 x
* The equation is y = 19 x
b.
- We need to find the height of 13 DVD cases
∵ y = 19 x
∵ x = 13
- Substitute the value of x in the equation
∴ y = 19 × 13
∴ y = 247 mm
* The height of 13 DVD cases is 247 mm
