Finding the Fourth Proportional to 1,188.72, 1,784.43 and 859.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.72 : 1,784.43 = 859.86 : x
2. Step 2: Convert to fraction form
   1,188.72/1,784.43 = 859.86/x
3. Step 3: Cross multiply
   1,188.72x = 1,784.43 × 859.86
4. Step 4: Simplify right side
   1,188.72x = 1,534,359.98
5. Step 5: Solve for x
   x = 1,534,359.98/1,188.72
6. Step 6: Final answer
   x = 1,290.77