- A ruler is used for measuring the length of an object
- A butterfly is a kind of object
- So, a ruler can be used to measure the length of a butterfly

- A ruler can be used to measure the length of a butterfly
- A metric ruler is a ruler with metric units
- Hence, a metric ruler can be used to measure the length of a butterfly

Hence, a metric ruler can be used to measure the length of a butterfly
Question
Which tool would be best to measure the length of a butterfly?

Context
- A ruler is used for measuring the length of an object 
- A metric ruler is a ruler with metric units 
- A butterfly is a kind of object