Superlesson
Project 8-1

Superlesson
Project 8-2

Superlesson
Project 8-3

Geometry

Chapter 8, Circles and Spheres

Circles and angles can be found in product logos. Below, you will examine some logos and the angles and arcs in them.

Part A, Inscribed Angles

1. Go to the Jet Express Web site to see a logo which uses a circle, an inscribed angle and one other angle.

a. Use a protractor to measure the inscribed angle.

b. What is the measure of its intercepted arc?

c. What is the measure of a central angle which intercepts the same arc as in 1b?

d. What is the measure of the other acute angle in this logo?

e. Is this a central angle? How do you know?

2. Now, go to the Volkswagen Web site to see a logo which is probably familiar to you. Use a compass and protractor to draw a logo which is geometrically similar, but larger than the one pictured. Give the measures of each of the central and inscribed angles in your drawing. Use these measures to find the measures of each of the intercepted arcs of the circle. Also include the measures of the arcs in your drawing.

Part B, Angles Formed by Secants and Tangents

3. Go to the Foreign Auto Tech Web site to see a logo consisting of a triangle formed by two secants and a diameter of the smaller circle.

a. Use your protractor to measure the acute angle formed by the two secants. What type of triangle is this?

b. The angle formed by the two secants intersects the endpoints of the diameter of the circle. What is the measure of the smaller intercepted arc?