Answer:
37%
Step-by-step explanation:
First to find the percent of decrease you have subtract the largest number by the smaller number. So 78 ft² - 49.14 ft². This would get you to 28.86 ft². Then you would divide the original number, (in this case 78) by the difference (28.86). Once you divide you get .37, you will have to multiply by 100 to get the percent. So the percent of decrease is 37%.