Mrs. Hanrahan’s precalculus class collected data on the length (in centimeters) of a pendulum and the time (in seconds) the pendulum took to complete one back-andforth swing (called its period). The theoretical relationship between a pendulum’s length and its period is

where g is a constant representing the acceleration due to gravity (in this case, g = 980 cm/s²). Here is a graph of period versus length, along with output from a linear regression analysis using these variables.

a. Give the equation of the least-squares regression line. Define any variables you use.

b. Use the model from part (a) to predict the period of a pendulum with length 80 cm.

period Vlength