Finding the Fourth Proportional to 1,106.31, 1,526.79 and 640.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,106.31 : 1,526.79 = 640.56 : x
2. Step 2: Convert to fraction form
   1,106.31/1,526.79 = 640.56/x
3. Step 3: Cross multiply
   1,106.31x = 1,526.79 × 640.56
4. Step 4: Simplify right side
   1,106.31x = 978,000.60
5. Step 5: Solve for x
   x = 978,000.60/1,106.31
6. Step 6: Final answer
   x = 884.02