Finding the Fourth Proportional to 1,042.99, 1,439.28 and 623.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,042.99 : 1,439.28 = 623.57 : x
2. Step 2: Convert to fraction form
   1,042.99/1,439.28 = 623.57/x
3. Step 3: Cross multiply
   1,042.99x = 1,439.28 × 623.57
4. Step 4: Simplify right side
   1,042.99x = 897,488.86
5. Step 5: Solve for x
   x = 897,488.86/1,042.99
6. Step 6: Final answer
   x = 860.50