Question

the graph represents the function where electricity usage in kilowatts per hour of a clock radio varies directly with the number of days it is plugged into the wall current. which is a reasonable estimate of the constant of variation? 0.25 kwh per day 0.50 kwh per day 2.40 kwh per day 4.00 kwh per day

Explanation:

Step1: Identify two points on the line

Let's take two easy - to - read points. Assume the line passes through (0, 0) and (8, 2).

Step2: Use the formula for the constant of variation (slope)

The formula for the constant of variation $k$ in a direct - variation $y = kx$ (where $y$ is electricity usage in kWh and $x$ is the number of days) is $k=\frac{y_2 - y_1}{x_2 - x_1}$. Substituting $x_1 = 0,y_1 = 0,x_2 = 8,y_2 = 2$ into the formula, we get $k=\frac{2 - 0}{8 - 0}=\frac{2}{8}=0.25$.

Answer:

0.25 kWh per day