Final answer:
The equation to find the total number of feet if you know the number of yards is 'feet = 3 × yards'. This is because one yard is equivalent to 3 feet.
Step-by-step explanation:
To express the total number of feet (feet) in terms of yards (yards), you will want to use the relationship that every yard is equal to 3 feet. So if you have a certain number of yards, you would multiply that number by 3 to find out how many feet you have. This can be written as an equation:
feet = 3 × yards
This equation means that for any given number of yards, you can find the equivalent number of feet by multiplying it by 3. For example, if you have 4 yards, you can find that you have 4 × 3 = 12 feet. Hence, option A (feet = 3 × yards) is the correct choice.