Finding the Fourth Proportional to 1,392.72, 1,921.52 and 994.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.72 : 1,921.52 = 994.05 : x
2. Step 2: Convert to fraction form
   1,392.72/1,921.52 = 994.05/x
3. Step 3: Cross multiply
   1,392.72x = 1,921.52 × 994.05
4. Step 4: Simplify right side
   1,392.72x = 1,910,081.99
5. Step 5: Solve for x
   x = 1,910,081.99/1,392.72
6. Step 6: Final answer
   x = 1,371.48