Finding the Fourth Proportional to 1,356.78, 1,872.32 and 859.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,356.78 : 1,872.32 = 859.70 : x
2. Step 2: Convert to fraction form
   1,356.78/1,872.32 = 859.70/x
3. Step 3: Cross multiply
   1,356.78x = 1,872.32 × 859.70
4. Step 4: Simplify right side
   1,356.78x = 1,609,633.50
5. Step 5: Solve for x
   x = 1,609,633.50/1,356.78
6. Step 6: Final answer
   x = 1,186.36