Finding the Fourth Proportional to 2,641.72, 3,961.88 and 997.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,641.72 : 3,961.88 = 997.78 : x
2. Step 2: Convert to fraction form
   2,641.72/3,961.88 = 997.78/x
3. Step 3: Cross multiply
   2,641.72x = 3,961.88 × 997.78
4. Step 4: Simplify right side
   2,641.72x = 3,953,084.63
5. Step 5: Solve for x
   x = 3,953,084.63/2,641.72
6. Step 6: Final answer
   x = 1,496.41