Finding the Fourth Proportional to 1,428.27, 1,970.91 and 838.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.27 : 1,970.91 = 838.73 : x
2. Step 2: Convert to fraction form
   1,428.27/1,970.91 = 838.73/x
3. Step 3: Cross multiply
   1,428.27x = 1,970.91 × 838.73
4. Step 4: Simplify right side
   1,428.27x = 1,653,051.49
5. Step 5: Solve for x
   x = 1,653,051.49/1,428.27
6. Step 6: Final answer
   x = 1,157.38