Teacher Outline: A.5 The Circle
I.
II.
Suggested Pacing:
a. 1-2 Days traditional
b. 1 Day Block
Warm Up Problems
NONE BEGINNING OF THE NEW NINE WEEKS
III.
Learning Objectives
a. Suggested Content Objective: The student will be able to write the equation of the
circle centered at the origin and at any arbitrary point. They will be able to use the
distance formula to find the length of the radius and to find an equation given two
points.
b. Suggested Approach: The students will be able to discuss the different ways on how to
find the equations of circles and to discuss how are circles used in real life after teacher
lecture.
IV.
Topic Outline
a. Equation of a circle centered at the origin and any radius R
i. Examples include
1. Write the equation of a circle with center (0, 0) and radius 5
x2 + y2 = 25
2. Write the equation of a circle with center (0 , 0) and radius √13
x2 + y2 = 13
3. Graph the circle x2 + y2 = 36
b. Equation of the circle with center at any point (h , k) and any radius R
i. Examples include
1. Write the equation of a circle with center (-5 , 8) and radius √20
(x + 5)2 + (y – 8)2 = 20
A.5 The Circle
Week 2.1
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Teacher Outline: A.5 The Circle
2. Write the equation of a circle with center (3 , -1) and radius 7
(x – 3)2 + (y + 1)2 = 49
3. Graph the circle with equation (x – 3)2 + (y + 1)2 = 4
c. Equation of a circle centered at any point and going through a certain point.
i. Examples include
1. Find the equation of the circle with center at (-3 , 1) and passing
through (2 , 4)
(x – 3)2 + (x + 1)2 = 26
2. Find the equation of the circle with center at (-2 , -2) and passing
through (3 , 5)
(x + 2)2 + (y + 2)2 = 74
3. Find the equation of the circle with center at (3 , 4) and passing through
(-1, 2)
(x – 3)2 + (y – 4)2 = 20
d. Write the equation of a circle given the graph.
i. Examples include
x2 + y 2 = 9
A.5 The Circle
(x + 6)2 + (y – 3)2 = 16
Week 2.1
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