Finding the Fourth Proportional to 1,358.64, 1,872.72 and 939.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,358.64 : 1,872.72 = 939.60 : x
2. Step 2: Convert to fraction form
   1,358.64/1,872.72 = 939.60/x
3. Step 3: Cross multiply
   1,358.64x = 1,872.72 × 939.60
4. Step 4: Simplify right side
   1,358.64x = 1,759,607.71
5. Step 5: Solve for x
   x = 1,759,607.71/1,358.64
6. Step 6: Final answer
   x = 1,295.12