Finding the Fourth Proportional to 1,445.28, 1,994.07 and 815.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,445.28 : 1,994.07 = 815.78 : x
2. Step 2: Convert to fraction form
   1,445.28/1,994.07 = 815.78/x
3. Step 3: Cross multiply
   1,445.28x = 1,994.07 × 815.78
4. Step 4: Simplify right side
   1,445.28x = 1,626,712.45
5. Step 5: Solve for x
   x = 1,626,712.45/1,445.28
6. Step 6: Final answer
   x = 1,125.53