Finding the Fourth Proportional to 1,111.02, 1,533.29 and 639.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.02 : 1,533.29 = 639.07 : x
2. Step 2: Convert to fraction form
   1,111.02/1,533.29 = 639.07/x
3. Step 3: Cross multiply
   1,111.02x = 1,533.29 × 639.07
4. Step 4: Simplify right side
   1,111.02x = 979,875.73
5. Step 5: Solve for x
   x = 979,875.73/1,111.02
6. Step 6: Final answer
   x = 881.96