Finding the Fourth Proportional to 1,391.64, 1,917.82 and 997.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.64 : 1,917.82 = 997.98 : x
2. Step 2: Convert to fraction form
   1,391.64/1,917.82 = 997.98/x
3. Step 3: Cross multiply
   1,391.64x = 1,917.82 × 997.98
4. Step 4: Simplify right side
   1,391.64x = 1,913,946.00
5. Step 5: Solve for x
   x = 1,913,946.00/1,391.64
6. Step 6: Final answer
   x = 1,375.32