Finding the Fourth Proportional to 1,405.03, 1,939.60 and 815.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.03 : 1,939.60 = 815.45 : x
2. Step 2: Convert to fraction form
   1,405.03/1,939.60 = 815.45/x
3. Step 3: Cross multiply
   1,405.03x = 1,939.60 × 815.45
4. Step 4: Simplify right side
   1,405.03x = 1,581,646.82
5. Step 5: Solve for x
   x = 1,581,646.82/1,405.03
6. Step 6: Final answer
   x = 1,125.70