Finding the Fourth Proportional to 1,071.96, 1,607.33 and 639.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,071.96 : 1,607.33 = 639.42 : x
2. Step 2: Convert to fraction form
   1,071.96/1,607.33 = 639.42/x
3. Step 3: Cross multiply
   1,071.96x = 1,607.33 × 639.42
4. Step 4: Simplify right side
   1,071.96x = 1,027,755.75
5. Step 5: Solve for x
   x = 1,027,755.75/1,071.96
6. Step 6: Final answer
   x = 958.76