1. HOW BIG IS AN ACRE? 43,560 Square Feet
1/3 of a Baseball Field
16 Tennis Courts
Bigger than a Soccer Field
How Big Is An Acre?
An acre is 43,560 square feet
Its approximately 1/3 of a BASEBALL FIELD
Its larger than a SOCCER FIELD
Its equal to 16 TENNIS COURTS
Its about 90 Yards of a FOOTBALL FIELD
Its nearly a little more than three lanes of an OLYMPIC SWIMMING POOL
Three Lanes of an Olympic Swimming Pool
Almost the Size of a Football Field

2. 43,560 ft2 ACRES AND AREA 209 Feet 209 Feet
How Do You Calculate an Acre in Area?
Use this visual as a simple demonstration of the math used in the Square Feet Calculation.
The Square Root of 43,560 is 209
- Therefore 209’ X 209’ = 43,560 Square Feet

3. 100’ 5,000 ft2 5,000 ft2 43,560 ft2 ACRES AND AREA 100 Feet 50 Feet
Step 2:
(Product)
divided by
(Square ft in an Acre)
Step 1:
(X) times (Y)
100’
X 50’
5,000 ft2
50 Feet
5,000 ft2
43,560 ft2
.12 Acres.
This simplified example can be used to demonstrate the conversion from square feet to acres.
Remember the term “acres” implies a measurement of area so it is not necessary label your product acres squared. If used as a measure of volume, secondary units will be used. (ie Acre Feet)
NOTE:
Students sometimes have difficulty with the notation for FEET ( ‘ ) and INCHES ( “ ).
A great way to get them to remember is syllables for each word matcher the number of marks used.
Inch-es (two syllables, two marks “ )
Feet (one syllable, one mark ‘ )
You may even see them “clapping out” the syllables in class.

4. Where in the World?
Use this slide to introduce the idea of the Latitude and Longitude Grid System.
You can show students where each of the continents are located on the Latitude and Longitude Grid
Check for understand by asking students which continents located at each of the following set of coordinates:
0 degrees W Longitude and 20 degrees N Longitude (Africa)
100 degrees E Longitude and 40 degrees North Latitude (Asia)
60 degrees W Longitude and 20 degrees South Latitude (South America)
You can differentiate instruction by asking to students to give the coordinates of remaining continents.
HISTORY:
Since earliest times, astronomers and mapmakers have used the equator to divide the world into northern and southern hemispheres. The starting point for longitude, however, has varied many times over the ages. It has been located in Egypt, Greece, Spain, France, and other places, depending on which country was preeminent at the time in the study of location by celestial observation. In 1884, the international community adopted Greenwich as the mean in order to standardize world mapmaking.
The use of grid lines (latitude and longitude) was first suggested by the Greek astronomer Hipparcus about 300 years before Christ. Shortly after, Hipparcus devised the method of fixing the location of places on earth by observation of the celestial bodies--the sun, moon and stars. He worked out the mathematics of spherical trigonometry, which allowed the results of these observations to be plotted on an earth that he perceived to be a sphere.
Some 75 years later (around 225 B.C.) Eratosthenes, another Greek mathematician and astronomer, measured the circumference of the earth (accurate to within 300 miles) raising the art of mapmaking to new standards of accuracy.

5. Latitude and Longitude to Feet
Point A
Point B
Point A minus Point B equals Change in Longitude
N ’
W ’
N ’
W ’
W ’
W ’
.518’
Point A minus Point B equals Change in Latitude
How Do We Convert Longitude and Latitude to Feet?
A “Waypoint” is made up of an X and a Y Coordinates
To help you to remember which coordinate is which they are designated identified
“W” for Longitude (X Coordinate)
“N” for Latitude (Y Coordinate)
To calculate the distance between two points.
- If the points are West and East of one another subtract the smaller Longitude from the larger Longitude which results in the CHANGE IN LONGITUDE.
- If the points are North and South of one another subtract the smaller Latitude from the larger Latitude which results in the CHANGE IN LATITUDE.
N ’
N ’
.419’
N ’
W ’
Point C

6. Latitude and Longitude to Feet
Multiplier
1 Minute of Longitude = 5,100 Feet *
Longitude lines measure location to the
WEST of the Prime Meridian ( W ’ )
*As you travel north or south of the equator longitude lines get closer together. Your constant will get smaller the further north you are go.
Multiplier
1 Minute of Latitude = 6,300 Feet
NOW THAT YOU HAVE THE CHANGE IN LATITUDE OR LONGITUDE HOW DO YOU CONVERT THAT TO FEET?
This is where things can get confusing so be sure to start with the globe explanation.
Our globe is a sphere, a ball so to speak; if we are to create a grid on s spherical object we cannot use a constant distance between degrees of Latitude and Longitude.
The “Y” coordinate or Latitude is represented by degrees north or south of the Equator with 0o representing the equatorial plane and 90o representing the North or South Pole. Each minute of latitude is equal to approximately 6,300 feet.
The “X” coordinate or Longitude is represented by degrees west or East of the Prime Meridian with 0o representing the Prime Meridian and 190o representing the International Date Line. Because all latitude lines meet at the north and south poles the get closer to one another as you approach those points. Therefore you must calculate the “Multiplier”. This can be done using a GPS unit, a computer program such as Google Earth, or a Measuring Wheel.
A major city block in your area should be one half a mile by one half mile and measure 2,640 Feet on each side. If you determine the change in Longitude from the north east corner to the north west corner and multiply it by 2,640 the product will be the linier feet in a minute of longitude at that latitude. (Or for the ease of this lesson you can use the same multiplier for both latitude and longitude)
The multipliers used in this lesson are actual calculations for Clovis, California.
Latitude lines measure location north or south of the equator ( N ’ ). They are always the same distance apart so this number remains the same.

7. Latitude and Longitude to Feet
Constant *
1 Minute of Longitude = 5,100 Feet
W ’
W ’
.518’
5,100 X
2,641 Feet Point A to Point B
Constant
1 Minute of Latitude = 6,300 Feet
N ’
N ’
.419’
6,300 X
2,639 Feet Point A to Point C

8. ACRES AND AREA
2,641 Feet
6,969,599 ft2
2,639 Feet

9. ACRES AND AREA 6,969,599 ft2 43,560 (feet2 / Acre) = 160 Acres2
A homestead act is one of three United States federal laws that gave an applicant ownership at no cost of farmland called a "homestead" – typically 160 acres
(65 hectares or one-fourth section) of undeveloped federal land west of the Mississippi River.