Superlesson
Project 8-2

Geometry

Chapter 8, Circles and Spheres

Being able to figure out arc measures and arc lengths of arcs is critical to mapping the planets. Below, you will view maps of Venus and Pluto and use given statistics to determine the extent of coverage of each of the maps.

Part A, Arcs and Central Angles

1. Go to the Venus Web site to see general information about Venus.

a. Now, go to the section on this Web site titled "Venusian Map." Click on the map to get a more detailed, larger picture. This map does not cover the whole Venusian surface. It only covers from -66.5 to 66.5 degrees latitude. See the illustration below of how much of the surface this map covers.

b. What is

c. What is the measure of arc AB?

2. Now, go to the Pluto Web site to see general information about Pluto.

a. Go to the section on this Web site titled "Map of the Surface of Pluto." Click on the map to get a more detailed, larger picture. Once again, this map does not cover Pluto's whole surface. Estimate the range in latitude this map covers and sketch a diagram of this range similar to the one given in 1a.
b. What is in your diagram of Pluto?

c. What is the measure of arc AB in your diagram of Pluto?

Part B, Arc Length and Sectors

3. Go back to the Venus Web site.

a. What is the radius of Venus in kilometers?

b. What is the circumference of Venus to the nearest kilometer?

4. Go back to the Pluto Web site.

a.What is the radius of Pluto in kilometers?

b. What is the circumference of Pluto to the nearest kilometer?

5. The map of Pluto covers a larger portion of the planet, yet it covers a smaller vertical distance. Why is this?