Finding the Fourth Proportional to 1,118.15, 1,542.98 and 620.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,118.15 : 1,542.98 = 620.72 : x
2. Step 2: Convert to fraction form
   1,118.15/1,542.98 = 620.72/x
3. Step 3: Cross multiply
   1,118.15x = 1,542.98 × 620.72
4. Step 4: Simplify right side
   1,118.15x = 957,758.55
5. Step 5: Solve for x
   x = 957,758.55/1,118.15
6. Step 6: Final answer
   x = 856.56