Finding the Fourth Proportional to 1,138.56, 1,570.82 and 641.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,138.56 : 1,570.82 = 641.12 : x
2. Step 2: Convert to fraction form
   1,138.56/1,570.82 = 641.12/x
3. Step 3: Cross multiply
   1,138.56x = 1,570.82 × 641.12
4. Step 4: Simplify right side
   1,138.56x = 1,007,084.12
5. Step 5: Solve for x
   x = 1,007,084.12/1,138.56
6. Step 6: Final answer
   x = 884.52