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 clock radio electricity usage 4.5 4 electricity usage (kwh) 3.5 3 2.5 2 1.5 1 0.5

Explanation:

Step1: Recall direct - variation formula

The formula for direct variation is $y = kx$, where $k$ is the constant of variation. In this case, if $y$ is electricity usage in kWh and $x$ is the number of days, $k=\frac{y}{x}$.

Step2: Estimate values from the graph

Let's assume we take a point on the graph. For example, when $x = 10$ days, $y\approx2.5$ kWh. Then $k=\frac{y}{x}=\frac{2.5}{10}=0.25$ kWh per day.

Answer:

0.25 kWh per day