Finding the Fourth Proportional to 1,339.12, 1,847.91 and 815.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.12 : 1,847.91 = 815.05 : x
2. Step 2: Convert to fraction form
   1,339.12/1,847.91 = 815.05/x
3. Step 3: Cross multiply
   1,339.12x = 1,847.91 × 815.05
4. Step 4: Simplify right side
   1,339.12x = 1,506,139.05
5. Step 5: Solve for x
   x = 1,506,139.05/1,339.12
6. Step 6: Final answer
   x = 1,124.72