Finding the Fourth Proportional to 1,385.61, 2,079.79 and 838.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.61 : 2,079.79 = 838.86 : x
2. Step 2: Convert to fraction form
   1,385.61/2,079.79 = 838.86/x
3. Step 3: Cross multiply
   1,385.61x = 2,079.79 × 838.86
4. Step 4: Simplify right side
   1,385.61x = 1,744,654.43
5. Step 5: Solve for x
   x = 1,744,654.43/1,385.61
6. Step 6: Final answer
   x = 1,259.12