Finding the Fourth Proportional to 1,111.27, 1,533.18 and 639.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.27 : 1,533.18 = 639.04 : x
2. Step 2: Convert to fraction form
   1,111.27/1,533.18 = 639.04/x
3. Step 3: Cross multiply
   1,111.27x = 1,533.18 × 639.04
4. Step 4: Simplify right side
   1,111.27x = 979,763.35
5. Step 5: Solve for x
   x = 979,763.35/1,111.27
6. Step 6: Final answer
   x = 881.66