$10$ inches is about the same length as $25$ centimeters. For each of the following pairs of measurements, decide which is longest.

1. $6$ inches or $12$ centimeters

   Hint (a):

   Knowing that $10$ inches is about the same length as $25$ centimeters, can you find how many centimeters are about equal to $1$ or $2$ inches? This may help with your estimations.

2. $25$ inches or $50$ centimeters

   Hint 1(b):

   Here, it may help to double (multiply by $2$) the original unit conversion provided above.

   Hint 2(b):

   Now we know that $20$ inches is about the same length as $50$ centimeters. With this, can you decide which measurement in part (b) is longest?

3. $15$ inches or $45$ centimeters

   Hint (c):

   Try using the suggestions in part (a) or (b).

   Answer (c):

   $45$ centimeters are longer than $15$ inches.

4. $35$ inches or $75$ centimeters

   Answer (d):

   $35$ inches are longer than $75$ centimeters.