Finding the Fourth Proportional to 2,428.78, 3,643.56 and 785.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,428.78 : 3,643.56 = 785.86 : x
2. Step 2: Convert to fraction form
   2,428.78/3,643.56 = 785.86/x
3. Step 3: Cross multiply
   2,428.78x = 3,643.56 × 785.86
4. Step 4: Simplify right side
   2,428.78x = 2,863,328.06
5. Step 5: Solve for x
   x = 2,863,328.06/2,428.78
6. Step 6: Final answer
   x = 1,178.92