Finding the Fourth Proportional to 1,405.67, 1,939.34 and 815.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.67 : 1,939.34 = 815.99 : x
2. Step 2: Convert to fraction form
   1,405.67/1,939.34 = 815.99/x
3. Step 3: Cross multiply
   1,405.67x = 1,939.34 × 815.99
4. Step 4: Simplify right side
   1,405.67x = 1,582,474.39
5. Step 5: Solve for x
   x = 1,582,474.39/1,405.67
6. Step 6: Final answer
   x = 1,125.78