Finding the Fourth Proportional to 1,445.31, 1,994.54 and 815.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,445.31 : 1,994.54 = 815.87 : x
2. Step 2: Convert to fraction form
   1,445.31/1,994.54 = 815.87/x
3. Step 3: Cross multiply
   1,445.31x = 1,994.54 × 815.87
4. Step 4: Simplify right side
   1,445.31x = 1,627,275.38
5. Step 5: Solve for x
   x = 1,627,275.38/1,445.31
6. Step 6: Final answer
   x = 1,125.90