A linear equation in slope-intercept form is given by:

Where:
b = starting height of tree = 4 feet = 48 inches
m = inches per year = 3 inches
x = the number of years of new growth
First, We convert the 4 feet in height to inches, to work in the same units. We know that 1 foot = 12 inches, therefore:

48 is the starting height of tree in inches
Next, the equation is:
