•cenozoic era (65 mya to present) • cretaceous period (146‒65 mya) • jurassic period (208‒146 mya) • triassic period (245‒208 mya) • paleozoic era (570‒245 mya) • proterozoic era (2,500‒570 mya) • archean era (3,800‒2,500 mya) • hadean era (4,600‒3,800 mya) for example, to calculate where to mark the cenozoic era, calculate: 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards 65 million years times start fraction 1 yard over 46 end is approximately equal to 1.4 yards ≈ the cenozoic era should be marked approximately 1.4 yards from the right end of the football field.