Finding the Fourth Proportional to 1,404.79, 1,938.46 and 815.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,404.79 : 1,938.46 = 815.21 : x
2. Step 2: Convert to fraction form
   1,404.79/1,938.46 = 815.21/x
3. Step 3: Cross multiply
   1,404.79x = 1,938.46 × 815.21
4. Step 4: Simplify right side
   1,404.79x = 1,580,242.67
5. Step 5: Solve for x
   x = 1,580,242.67/1,404.79
6. Step 6: Final answer
   x = 1,124.90