The answer is B.) The diameter of the fir tree when planted and 20 inches
Step-by-step explanation:
The y-intercept is the initial diameter of the fir tree (10 inches). At the end of 50 years, the tree's diameter is 30 inches. Therefore, 30 − 10 = 20 inches of growth occurred over the 50 year period. The diameter of the fir tree when planted. The fir tree's diameter was 10 inches when it was planted.