Finding the Fourth Proportional to 1,111.32, 1,533.84 and 639.29

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.32 : 1,533.84 = 639.29 : x
2. Step 2: Convert to fraction form
   1,111.32/1,533.84 = 639.29/x
3. Step 3: Cross multiply
   1,111.32x = 1,533.84 × 639.29
4. Step 4: Simplify right side
   1,111.32x = 980,570.01
5. Step 5: Solve for x
   x = 980,570.01/1,111.32
6. Step 6: Final answer
   x = 882.35