Download Chapter 10 Circle Geometry

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Chapter 10 Circle Geometry
Lesson #1 Exploring Angles in a Circle
Circle Terminology
Chord
Central Angle
Inscribed Angle
Arc (of a circle)
Relationships between angles in a circle
Label the centre of the circle C.
Construct a chord AB and a central angle BCA
Create the inscribed angle BDA
What is the measure of BDA ?
How do the measures of BCA and BDA compare?
Create a second inscribed angle BEA
What is the measure of angle BEA ?
Date:
Math 9
Properties of a circle
Inscribed Angles
 Inscribed angles subtended by the same arc are congruent
Central and Inscribed
 The measure of the central angle is equal to twice the measure of the inscribed angle
subtended by the same arc.
EXAMPLE #1
Determine the measure of ABC and AEC. Explain how you got your answers
EXAMPLE #2 RIGHT ANGLES
Determine the length of chord BC in each of the following.
EXAMPLE #3 PROBLEM SOLVING
Point C is the centre of a circular flowerbed with a radius of 8 m. The flowerbed is divided
as shown in the diagram. If ABD = 45°, determine the length of AD to the nearest tenth.
EXAMPLE #4 EXTRA PRACTICE
Solve for the missing angles in each diagram
Homework
1. Pg. 382 #3 - 8, 10 - 15, 18,19