Answer: An example:
Measure the distance between the center of the spreading center (red) and the border between dark yellow and light green (65 Ma point) I measured 2 cm Since the scale on the map is 1 cm = 475 km, calculate the real distance that the plate has moved over the past 65 Ma 2 cm * 475 km/cm = 950 km = 95,000,000 cm = 9.5 * 107 cm Determine the length of time that the plate has been moving65 million years = 65,000,000 years = 6.5 * 107 yearsUse the above equation to calculate spreading rateR = d/t or R = 9.5 * 107 cm / 6.5 * 107 years = 1.46 cm/yr
Explanation: