Since the graph shows a proportional relationship between x and y, the cost of 20 m of tinsel is equal to 7 pounds (£).
In Mathematics and Geometry, a proportional relationship is a type of relationship that passes through the origin (0, 0) and produces equivalent ratios as represented by the following mathematical equation:
y = kx
Where:
- y represents the y-variable.
- x represents the x-variable.
- k is the constant of proportionality.
Next, we would determine the constant of proportionality (k) by using various data points as follows:
Constant of proportionality, k = y/x
Constant of proportionality, k = 7/20
Therefore, the required linear function for y(x) is given by;
y = kx
y = 7/20(x)
When x is 20, the value of y is given by;
y = 7/20(20)
y = 7 pounds (£).
Complete Question;
Look at the graph below. How much would 20 m of tinsel cost? Give your answer in pounds (£).