Finding the Fourth Proportional to 1,111.52, 1,533.79 and 639.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.52 : 1,533.79 = 639.29 : x
2. Step 2: Convert to fraction form
   1,111.52/1,533.79 = 639.29/x
3. Step 3: Cross multiply
   1,111.52x = 1,533.79 × 639.29
4. Step 4: Simplify right side
   1,111.52x = 980,532.62
5. Step 5: Solve for x
   x = 980,532.62/1,111.52
6. Step 6: Final answer
   x = 882.16