Finding the Fourth Proportional to 1,111.29, 1,533.42 and 639.26

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.29 : 1,533.42 = 639.26 : x
2. Step 2: Convert to fraction form
   1,111.29/1,533.42 = 639.26/x
3. Step 3: Cross multiply
   1,111.29x = 1,533.42 × 639.26
4. Step 4: Simplify right side
   1,111.29x = 980,246.40
5. Step 5: Solve for x
   x = 980,246.40/1,111.29
6. Step 6: Final answer
   x = 882.08