Finding the Fourth Proportional to 1,114.69, 1,538.24 and 642.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,114.69 : 1,538.24 = 642.57 : x
2. Step 2: Convert to fraction form
   1,114.69/1,538.24 = 642.57/x
3. Step 3: Cross multiply
   1,114.69x = 1,538.24 × 642.57
4. Step 4: Simplify right side
   1,114.69x = 988,426.88
5. Step 5: Solve for x
   x = 988,426.88/1,114.69
6. Step 6: Final answer
   x = 886.73