Finding the Fourth Proportional to 1,138.72, 1,708.59 and 591.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.72 : 1,708.59 = 591.30 : x
2. Step 2: Convert to fraction form
   1,138.72/1,708.59 = 591.30/x
3. Step 3: Cross multiply
   1,138.72x = 1,708.59 × 591.30
4. Step 4: Simplify right side
   1,138.72x = 1,010,289.27
5. Step 5: Solve for x
   x = 1,010,289.27/1,138.72
6. Step 6: Final answer
   x = 887.21