Eratosthenes and Earth's Geometry

Who was Eratosthenes?

• Greek librarian

• Roman emperor

• Egyptian pharaoh

• Persian scholar

What everyday observation suggested to ancient Greeks that the Earth might be spherical?

• The changing phases of the moon

• The disappearance of ships below the horizon

• The movement of stars across the night sky

• The occurrence of solar eclipses

Approximately when did Eratosthenes live?

• 100 AD

• 300 BC

• 500 BC

• 700 AD

What observation did Eratosthenes make about shadows in Syene and Alexandria on the longest day of the year?

• Both cities had no shadows

• Both cities had shadows of equal length

• Syene had no shadow while Alexandria had one

• Alexandria had no shadow while Syene had one

What did the difference in shadow observations between Syene and Alexandria prove about the Earth?

• The Earth is flat

• The Earth is a perfect cube

• The Earth's surface is curved

• The Earth is stationary

What was the estimated distance between Alexandria and Syene?

• 500 km

• 800 km

• 1000 km

• 1200 km

What assumption did Eratosthenes make about the sun's rays?

• They converge at a point

• They diverge from a point

• They are parallel

• They are perpendicular to the Earth's surface

What is a line that intersects two parallel lines called?

• A perpendicular line

• A tangent line

• A transversal

• A chord

What is true about alternate interior angles formed by two parallel lines intersected by a transversal?

• They are supplementary

• They are complementary

• They are equal

• They sum to 90 degrees

What was Eratosthenes' calculated central angle of the Earth based on his measurements?

• 5 degrees

• 7.5 degrees

• 10 degrees

• 15 degrees