Finding the Fourth Proportional to 1,074.78, 1,608.93 and 642.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,074.78 : 1,608.93 = 642.78 : x
2. Step 2: Convert to fraction form
   1,074.78/1,608.93 = 642.78/x
3. Step 3: Cross multiply
   1,074.78x = 1,608.93 × 642.78
4. Step 4: Simplify right side
   1,074.78x = 1,034,188.03
5. Step 5: Solve for x
   x = 1,034,188.03/1,074.78
6. Step 6: Final answer
   x = 962.23