Finding the Fourth Proportional to 1,111.08, 1,533.54 and 639.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.08 : 1,533.54 = 639.24 : x
2. Step 2: Convert to fraction form
   1,111.08/1,533.54 = 639.24/x
3. Step 3: Cross multiply
   1,111.08x = 1,533.54 × 639.24
4. Step 4: Simplify right side
   1,111.08x = 980,300.11
5. Step 5: Solve for x
   x = 980,300.11/1,111.08
6. Step 6: Final answer
   x = 882.29