Finding the Fourth Proportional to 1,081.05, 1,492.05 and 638.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.05 : 1,492.05 = 638.93 : x
2. Step 2: Convert to fraction form
   1,081.05/1,492.05 = 638.93/x
3. Step 3: Cross multiply
   1,081.05x = 1,492.05 × 638.93
4. Step 4: Simplify right side
   1,081.05x = 953,308.05
5. Step 5: Solve for x
   x = 953,308.05/1,081.05
6. Step 6: Final answer
   x = 881.84