This week
Lessons 116, 117, 118, 119 & 120
STILLWATER CROSSING · THE COURSE NOTES · BRIDGE MATH 5/6
Week 25 · Circles and Percents
Papers
Test 12 to do at home
Method
No calculators, ever · show every step
Instructional notes
Circles
Circle • Closed figure with all points the same distance from its center • Named by its center
Radius • Line segment from the center to any point on the (radii plural) circle
Chord • Any line segment with its endpoints on the circle
Diameter • Line segment through the center point with both endpoints on the circle • A special kind of chord Arc • Curved part of the circle Semicircle • Special arc that is half of the circle
Sector • Closed figure formed by an angle at the center of a circle and its arc
Example
Draw and label.
Practice
Use the circles to complete. Name the circle P. P
Draw two radii that do not form a diameter.
Draw a sector on the circle.
Draw a chord.
Instructional notes
Angles in a Circle
Central Angle • vertex at the center • radii sides • sum of all in a circle will be 360°
EXAMPLE PROBLEM
Measure the central angles and then find their sum.
mAOB = 155°
mBOC = 120°
mCOA = + 85° 360°
Practice
A circle has 4 central angles. If the measures of the first 2 angles are 85°, and 15°, and the last two angles are congruent to each other, what is the measure of the third and fourth angle?
Instructional notes
Percents Percent • Another way to express a fraction or decimal • Parts (numerator) per hundred (denominator)
• %
Common Fraction-Percent Equivalents
Example
Fraction Decimal Percent
2
Practice
Fraction Fraction Decimal Decimal Percent Percent Fraction Fraction Decimal Decimal Percent Percent 4
✍ In your own words
explain the relationship between fractions, decimals and percents. Suggested Answer: Fractions, decimals, and percents are three different ways to show the same value, they are just different languages used to describe a part of a whole.
Homework this week
| Work-text | Lesson 116 | Lesson 117 | Lesson 118 | Lesson 119 | Lesson 120 |
|---|---|---|---|---|---|
| Speed drill | 116 | 117 | 118 | 120 |
Terms on the record
| Term | Meaning |
|---|---|
| semicircle | Semicircle • Special arc that is half of the circle |
| circles | Circle • Closed figure with all points the same |
| percents | Percent • Another way to express a fraction or decimal |
STILLWATER CROSSING // BRIDGE MATH // PENUMBRA · steady on