Finding the Fourth Proportional to 1,301.76, 1,950.72 and 642.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,301.76 : 1,950.72 = 642.88 : x
2. Step 2: Convert to fraction form
   1,301.76/1,950.72 = 642.88/x
3. Step 3: Cross multiply
   1,301.76x = 1,950.72 × 642.88
4. Step 4: Simplify right side
   1,301.76x = 1,254,078.87
5. Step 5: Solve for x
   x = 1,254,078.87/1,301.76
6. Step 6: Final answer
   x = 963.37