Unit 12 Lesson 4 Angle Measures and Segments
Unit 12 Lesson 4: Angle Measures and Segments
Lesson Overview
Angle Measures and Segments
What You Will Learn
- Angles and arcs formed by intersecting either within a circle or outside a circle
- Finding the measures of angles formed by chords, secants, and tangents
- Finding the lengths of segments associated with circles
Overview
In this lesson, you will learn about angles and arcs formed by intersecting either within a circle or outside a circle. You will show your learning by finding the measures of angles formed by chords, secants, and tangents. You will also find the lengths of segments associated with circles.
Essential Understanding
Angles formed by intersecting lines have a special relationship to the related arcs formed when the lines intersect a circle. There is a special relationship between two intersecting chords, two intersecting secants, or a secant that intersects a tangent. This relationship allows you to find the lengths of unknown segments.
- Read pages 517-524
This course is based on a textbook that is viewable by clicking on the textbook icon. Keep the textbook open while you go through the lesson so that you may refer to it throughout the lesson.
Lesson 4: Angle Measures and Segments
Resource Videos
Angle Measures by Chords, Secants, and Tangents
Segment Lengths related to Circles
Proceed to Next Page
Prepare for Application
Instructions
You have now studied Angle Measures and Segments. It is now time to demonstrate your learning.
Try the activities below on your own. You should be able to answer these before beginning the practice.
Create a journal extra called 'Unit 12: Lesson 4 activities' and do these activities in your journal.
Activity 1
What is the value of each variable?
- A departing space probe sends back a picture of Earth as it crosses Earth's equator. The angle formed by the two tangents to the equator is 20°. What is the measure of the arc of the equator that is visible to the space probe?
- Refer to Problem 2 on page 519 of your online textbook. Is the probe from question 1 or the geostationary satellite from Problem 2 closer to the Earth? Explain.
What is the value of the variable to the nearest tenth?
