Finding the Fourth Proportional to 1,404.90, 1,939.15 and 815.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,404.90 : 1,939.15 = 815.63 : x
2. Step 2: Convert to fraction form
   1,404.90/1,939.15 = 815.63/x
3. Step 3: Cross multiply
   1,404.90x = 1,939.15 × 815.63
4. Step 4: Simplify right side
   1,404.90x = 1,581,617.18
5. Step 5: Solve for x
   x = 1,581,617.18/1,404.90
6. Step 6: Final answer
   x = 1,125.79