Finding the Fourth Proportional to 1,345.12, 1,856.54 and 813.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.12 : 1,856.54 = 813.89 : x
2. Step 2: Convert to fraction form
   1,345.12/1,856.54 = 813.89/x
3. Step 3: Cross multiply
   1,345.12x = 1,856.54 × 813.89
4. Step 4: Simplify right side
   1,345.12x = 1,511,019.34
5. Step 5: Solve for x
   x = 1,511,019.34/1,345.12
6. Step 6: Final answer
   x = 1,123.33