Finding the Fourth Proportional to 1,124.34, 1,687.72 and 638.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,124.34 : 1,687.72 = 638.34 : x
2. Step 2: Convert to fraction form
   1,124.34/1,687.72 = 638.34/x
3. Step 3: Cross multiply
   1,124.34x = 1,687.72 × 638.34
4. Step 4: Simplify right side
   1,124.34x = 1,077,339.18
5. Step 5: Solve for x
   x = 1,077,339.18/1,124.34
6. Step 6: Final answer
   x = 958.20