Finding the Fourth Proportional to 1,978.72, 2,968.80 and 939.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.72 : 2,968.80 = 939.04 : x
2. Step 2: Convert to fraction form
   1,978.72/2,968.80 = 939.04/x
3. Step 3: Cross multiply
   1,978.72x = 2,968.80 × 939.04
4. Step 4: Simplify right side
   1,978.72x = 2,787,821.95
5. Step 5: Solve for x
   x = 2,787,821.95/1,978.72
6. Step 6: Final answer
   x = 1,408.90