Finding the Fourth Proportional to 1,016.98, 1,403.61 and 623.95

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.98 : 1,403.61 = 623.95 : x
2. Step 2: Convert to fraction form
   1,016.98/1,403.61 = 623.95/x
3. Step 3: Cross multiply
   1,016.98x = 1,403.61 × 623.95
4. Step 4: Simplify right side
   1,016.98x = 875,782.46
5. Step 5: Solve for x
   x = 875,782.46/1,016.98
6. Step 6: Final answer
   x = 861.16