Finding the Fourth Proportional to 1,385.83, 2,079.69 and 769.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.83 : 2,079.69 = 769.15 : x
2. Step 2: Convert to fraction form
   1,385.83/2,079.69 = 769.15/x
3. Step 3: Cross multiply
   1,385.83x = 2,079.69 × 769.15
4. Step 4: Simplify right side
   1,385.83x = 1,599,593.56
5. Step 5: Solve for x
   x = 1,599,593.56/1,385.83
6. Step 6: Final answer
   x = 1,154.25