Finding the Fourth Proportional to 1,438.92, 2,156.54 and 918.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,438.92 : 2,156.54 = 918.72 : x
2. Step 2: Convert to fraction form
   1,438.92/2,156.54 = 918.72/x
3. Step 3: Cross multiply
   1,438.92x = 2,156.54 × 918.72
4. Step 4: Simplify right side
   1,438.92x = 1,981,256.43
5. Step 5: Solve for x
   x = 1,981,256.43/1,438.92
6. Step 6: Final answer
   x = 1,376.91