Finding the Fourth Proportional to 2,211.67, 3,315.45 and 978.42

Step by Step Solution

1. Step 1: Write the proportion equation
   2,211.67 : 3,315.45 = 978.42 : x
2. Step 2: Convert to fraction form
   2,211.67/3,315.45 = 978.42/x
3. Step 3: Cross multiply
   2,211.67x = 3,315.45 × 978.42
4. Step 4: Simplify right side
   2,211.67x = 3,243,902.59
5. Step 5: Solve for x
   x = 3,243,902.59/2,211.67
6. Step 6: Final answer
   x = 1,466.72