Finding the Fourth Proportional to 753.42, 1,042.56 and 642.72

Step by Step Solution

1. Step 1: Write the proportion equation
   753.42 : 1,042.56 = 642.72 : x
2. Step 2: Convert to fraction form
   753.42/1,042.56 = 642.72/x
3. Step 3: Cross multiply
   753.42x = 1,042.56 × 642.72
4. Step 4: Simplify right side
   753.42x = 670,074.16
5. Step 5: Solve for x
   x = 670,074.16/753.42
6. Step 6: Final answer
   x = 889.38