Answer
a) The equation of the line that goes through the points is $y = 2x$, which is a linear equation. This proves that the data are linear.
b) 20 inches
c) No, the new information affects how we see the data.
Work Step by Step
a)
$m = \frac{8-2}{4-1}$
$m = 6/3 = 2$
$y = mx + b$
$8 = 2 * 4 + b$
$8= 8 +b$
$8-8 = 8-8 + b$
$0 = b$
$y = 2x$
b)
$y = 2 * 10 $
$y = 20$
c)
With the 10 year dimension at 43 inches and the 14 year dimension at 49 inches, these data points do not fit in the equation we previously used to determine the size. The relationship between time and circumference doesn't appear to be linear.
