Working with conversions. We will be

converting kilometers to inches. Our first example…2 kilometers converts into how many inches? Here is our game plan… We begin at kilometers…we move on to meters…then we have centimeters…we finish with…inches. Three conversion factors are

needed. Our first conversion factor shows that

one inch is equal to 2.54 centimeters. This measurement is exact!

The conversion factors can be made into… ratios that are both equal to each other.

Both factors can be made into one. Our next factor shows that 100 centimeters are equal to one meter. Both factors can be made into ratios that are equal to

each other. Both factors can be made into one. The last factor shows that 1,000

meters are equal to one kilometer. Again, both factors can be made into ratios that are equal. Both factors can be made… …into one. Now, let’s work through our example.

Begin with two kilometers. Plug in the… first conversion factor which is 1,000 meters over 1 kilometer times 100 centimeters… …over 1 meter times 1 inch over 2.54

centimeters. What you are converting to… …is on top which are inches. The plan is

to insert one label to cancel out… …another label. Kilometers cancel. Meters cancel.

Centimeters cancel which leaves inches. Multiplication is next. Two times 1,000

equals 2,000. 2,000 times 100 equals… …200,000. 200,000 times inches.

Continue to multiply 1 times 1 times 2.54. Last, divide by 2.54 to get 78,740.16 inches. This is the solution. Now, we convert inches back to kilometers. 78,740.16 inches convert into how many

kilometers? The game plan is to go from… …inches to centimeters to meters to

kilometers. Here are our three conversion factors.

Again, one inch is equal to 2.54 centimeters. You are going to use the one that has the centimeters on top. The next conversion factor is 100

centimeters equals one meter. The ratio… …with the meters on top is the one we

need. The next conversion factor is 1,000

meters equals one kilometer. You will use… …the one with kilometers on top. Next, plug it into our problem. Again, everything we… …are converting to needs to be on top. The plan is to insert one label to cancel… …another label. Everything cancels out

except kilometers. We will multiply all the top values. Next, we will multiply the bottom values. Last we will divide. The answer is 2

kilometers. So, 2 kilometers equals 78,741.16 inches. Thanks and take care!