Finding the Fourth Proportional to 1,941.12, 2,911.89 and 642.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,941.12 : 2,911.89 = 642.72 : x
2. Step 2: Convert to fraction form
   1,941.12/2,911.89 = 642.72/x
3. Step 3: Cross multiply
   1,941.12x = 2,911.89 × 642.72
4. Step 4: Simplify right side
   1,941.12x = 1,871,529.94
5. Step 5: Solve for x
   x = 1,871,529.94/1,941.12
6. Step 6: Final answer
   x = 964.15