Finding the Fourth Proportional to 1,345.64, 1,856.63 and 785.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.64 : 1,856.63 = 785.78 : x
2. Step 2: Convert to fraction form
   1,345.64/1,856.63 = 785.78/x
3. Step 3: Cross multiply
   1,345.64x = 1,856.63 × 785.78
4. Step 4: Simplify right side
   1,345.64x = 1,458,902.72
5. Step 5: Solve for x
   x = 1,458,902.72/1,345.64
6. Step 6: Final answer
   x = 1,084.17