Final answer:
Estimating 42% of 78 to be 45 is not a reasonable answer due to the estimation process.
Step-by-step explanation:
No, the answer is not reasonable. To estimate 42% of 78, we can start by finding 10%, which is equivalent to dividing 78 by 10, resulting in 7.8. Since 42% is more than four times 10%, we can estimate it to be around 4 times 7.8, or 31.2. Therefore, the student's answer of 45 is not a reasonable estimation.
Learn more about Estimating with Percents