RADIUS
6400 kilometers
(1)
The radius of the Earth is approximately 6400 kilometers.
How far would you travel, in kilometers, in going around the equator?
(2)
What is the speed of a point on the equator in kilometers
per hour as the Earth rotates on its axis?
(3)
(Extra Credit) If the radius of the Earth's orbit around the
Sun is 150 million kilometers, what is the speed of the Earth in its orbit in kilometers per
hour?
Part (2)
Angles
An angle is formed between two straight lines that meet at a point called the vertex of the angle.
The size of an angle is determined by the difference in direction of the two sides and is a fraction
of a full circle. The ancient Babylonian astronomers divided a circle into 360 parts or degrees.
(Apparently this was based on the fact that there are approximately 365 days in the year.
Exercise
(2A)
1. Using your protractor, measure the value in degrees for angles A, B, C, and D on your
Data Page. Record the value of the angle beside the vertex.
Exercise
(2B)
1. Using you protractor, measure and record each of the three angles in each triangle in the
figure on your Data Page.
2. What do you conclude about the sum of the angles in any triangle?
Exercise
(2C)
Using your protractor, construct the following angles on your Data Page: 25", 130", and 315".
