Finding the Fourth Proportional to 1,428.30, 1,971.59 and 904.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.30 : 1,971.59 = 904.68 : x
2. Step 2: Convert to fraction form
   1,428.30/1,971.59 = 904.68/x
3. Step 3: Cross multiply
   1,428.30x = 1,971.59 × 904.68
4. Step 4: Simplify right side
   1,428.30x = 1,783,653.52
5. Step 5: Solve for x
   x = 1,783,653.52/1,428.30
6. Step 6: Final answer
   x = 1,248.79