Let us take time by x variable and height of the candle by y variable.
We can setup two coordinates form the given statements:
After 38 minutes, the candle was 11.2 inches tall : (38, 11.2)
Eighteen minutes later, it was 10.75 inches tall : (56,10.75).
We need to write slope -intercept form of the equation first.
Slope-intercept form is :
y-y1 = m(x-x1).
<em>In order to find slope-intercept form we need to find the slope of the given equation.</em>
Slope between (38, 11.2) and (56, 10.75) points :
Let us apply slope-intercept form y-y1 = m(x-x1).
<h3>y- 11.2 = -0.025 (x-38)</h3>Now, we need to find the height of the candle after 4 hours.
We took time in minutes.
Therefore, 4 hours = 4× 60 = 240 minutes.
In order to find the height of the candle after 4 hours, we need to plug x=240 in above slope-intercept form.
y- 11.2 = -0.025 (240-38)
y-11.2 = -0.025 ( 202)
y-11.2 = -5.05
Adding 11.2 on both sides, we get
y-11.2+11.2 = -5.05+11.2
y = 6.15
We need to round it to the tenth place.
Therefore, y = 6.15.
<h3>Therefore, the height of the candle after 4 hours is 6.15 inches.</h3>