Finding the Fourth Proportional to 1,139.91, 1,573.05 and 635.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.91 : 1,573.05 = 635.76 : x
2. Step 2: Convert to fraction form
   1,139.91/1,573.05 = 635.76/x
3. Step 3: Cross multiply
   1,139.91x = 1,573.05 × 635.76
4. Step 4: Simplify right side
   1,139.91x = 1,000,082.27
5. Step 5: Solve for x
   x = 1,000,082.27/1,139.91
6. Step 6: Final answer
   x = 877.33