Finding the Fourth Proportional to 1,191.72, 1,786.62 and 542.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,191.72 : 1,786.62 = 542.88 : x
2. Step 2: Convert to fraction form
   1,191.72/1,786.62 = 542.88/x
3. Step 3: Cross multiply
   1,191.72x = 1,786.62 × 542.88
4. Step 4: Simplify right side
   1,191.72x = 969,920.27
5. Step 5: Solve for x
   x = 969,920.27/1,191.72
6. Step 6: Final answer
   x = 813.88