Answer:
342 inches, 28.5 feet, 9.5 yards.
Explanation:
The conversion rates you need to know are as follows:
1 foot = 12 inches
1 yard = 3 feet
Because there are 3 feet in a yard, we know that there must be are 36 inches in a yard. First, we find how many inches are in 10.5 feet and 3.5 yards. This would be 10.5 * 12 resulting in 126 inches. Also, 3.5 yards as we know is 36 inches so we do 3.5 * 36 which results again in 126. Finding the sum (126 + 126 + 90) we can see that this ribbon is 342 inches long. To find feet we divide this by 12. To find yards, we divide it by 36.