Let's work through the conversions step-by-step:
### Part (a): Convert 538 meters (m) to hectometers (hm)
We know that:
[tex]\[ 1 \text{ hectometer (hm)} = 100 \text{ meters (m)} \][/tex]
To convert from meters to hectometers, we need to divide the number of meters by 100:
[tex]\[ 538 \text{ m} = \frac{538}{100} \text{ hm} \][/tex]
Doing the division:
[tex]\[ 538 \text{ m} = 5.38 \text{ hm} \][/tex]
So,
[tex]\[ \boxed{5.38 \text{ hm}} \][/tex]
### Part (b): Convert 7.4 meters (m) to decimeters (dm)
We know that:
[tex]\[ 1 \text{ meter (m)} = 10 \text{ decimeters (dm)} \][/tex]
To convert from meters to decimeters, we need to multiply the number of meters by 10:
[tex]\[ 7.4 \text{ m} = 7.4 \times 10 \text{ dm} \][/tex]
Performing the multiplication:
[tex]\[ 7.4 \text{ m} = 74 \text{ dm} \][/tex]
So,
[tex]\[ \boxed{74 \text{ dm}} \][/tex]