Monday, January 25
EQ: How can you distinguish between when to use area and when to use perimeter?
Your family are the proud owners of a new circular swimming pool with a diameter of 25 feet and you are
eager to dive in. However, you quickly discover that having a new pool requires making many decisions about
other purchases.
1. The first concern is a solar pool cover. Online research indicates that circular pool covers come in the
following sizes: 400, 500, and 600 square feet. Friends recommend that you buy a pool cover with very
little overhang. Which size is best for your needs? Explain.
2. You decide to build a circular concrete patio 6 feet wide all around the pool. Draw a sketch of you pool
with the patio. What is the area covered by your patio. What is the area covered by your patio?
Explain.
3. State law requires that all pools be enclosed by a fence to prevent accidents. You decide to completely
enclose the pool and patio with a stockade fence. How many feet of fencing do you need? Explain.
4. Next, you decide to stain the new fence. The paint store recommends a stain that covers 500 square
feet per gallon. If the stockade fence has a height of 5 feet, how many gallons of stain should you buy?
Explain.
5. Lastly, you decide to plant a circular flower garden near the pool and patio but outside the fence. You
measure that a circle of circumference 30 feet would fit. What is the length of the corresponding
diameter of the flower garden?
6. _________ formulas are used when you are measuring the amount of region ________ a plane figure.
7. _________ formulas are used when you measuring the length __________ a plane figure.
8. A stop sign is in the shape of a regular octagon (an 8-sided polygon with equal sides and angles). A
regular octagon can be created using 8 triangles of equal area. One triangle that makes up a stop sign
has a base of 15 inches and a height of 18 inches. Calculate the area of the stop sign.
Tuesday, January 26
EQ: How can you measure the size of angles with a protractor?
Introduction (Read!)
You may have wondered why a right angle measures 90 degrees. Why not 100 degrees? As with much of the
mathematics that we use today, the measurement of angles has a rich history, going back to ancient times
when navigation of the oceans and surveying the land were priorities. The ancient Babylonian culture use a
base 60 number system, which at least in part led to the circile being dicided in 360 equal sectors. The angle of
each sector was simply defined to measure 1 degree and so today we say there are 360 degrees in a circle.
A protractor is a device for measuring the size of angles in degrees. Place the vertex of angle at the center of
the protractor (often a hole in the center of the baseline) and place one side of the angle along the baseline of
the protractor. Where the other side of the angle meets the appropriate scale on the semicircle of the
measure of the angles in degrees.
Obtuse angle is an angle that measures greater than 90 degrees.
Acute angles measures less than 90 degrees.
Right angles measure 90 degrees exactly.
Using the provided protractor, practice measuring each of the angles. Also, determine if each angle is acute,
obtuse, or right.
Classifying Triangles
Using the chart, classify the triangles.
Wednesday, January 27
The angles of a triangle, when added together will always equal 180 degrees.