Finding the Fourth Proportional to 1,142.65, 1,576.82 and 638.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.65 : 1,576.82 = 638.53 : x
2. Step 2: Convert to fraction form
   1,142.65/1,576.82 = 638.53/x
3. Step 3: Cross multiply
   1,142.65x = 1,576.82 × 638.53
4. Step 4: Simplify right side
   1,142.65x = 1,006,845.37
5. Step 5: Solve for x
   x = 1,006,845.37/1,142.65
6. Step 6: Final answer
   x = 881.15