Finding the Fourth Proportional to 1,945.98, 2,919.42 and 647.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,945.98 : 2,919.42 = 647.55 : x
2. Step 2: Convert to fraction form
   1,945.98/2,919.42 = 647.55/x
3. Step 3: Cross multiply
   1,945.98x = 2,919.42 × 647.55
4. Step 4: Simplify right side
   1,945.98x = 1,890,470.42
5. Step 5: Solve for x
   x = 1,890,470.42/1,945.98
6. Step 6: Final answer
   x = 971.47