Finding the Fourth Proportional to 1,020.87, 1,408.89 and 622.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.87 : 1,408.89 = 622.50 : x
2. Step 2: Convert to fraction form
   1,020.87/1,408.89 = 622.50/x
3. Step 3: Cross multiply
   1,020.87x = 1,408.89 × 622.50
4. Step 4: Simplify right side
   1,020.87x = 877,026.98
5. Step 5: Solve for x
   x = 877,026.98/1,020.87
6. Step 6: Final answer
   x = 859.10