Finding the Fourth Proportional to 1,061.28, 1,464.02 and 641.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.28 : 1,464.02 = 641.40 : x
2. Step 2: Convert to fraction form
   1,061.28/1,464.02 = 641.40/x
3. Step 3: Cross multiply
   1,061.28x = 1,464.02 × 641.40
4. Step 4: Simplify right side
   1,061.28x = 939,019.22
5. Step 5: Solve for x
   x = 939,019.22/1,061.28
6. Step 6: Final answer
   x = 884.80