Finding the Fourth Proportional to 1,428.56, 1,971.78 and 904.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.56 : 1,971.78 = 904.88 : x
2. Step 2: Convert to fraction form
   1,428.56/1,971.78 = 904.88/x
3. Step 3: Cross multiply
   1,428.56x = 1,971.78 × 904.88
4. Step 4: Simplify right side
   1,428.56x = 1,784,224.29
5. Step 5: Solve for x
   x = 1,784,224.29/1,428.56
6. Step 6: Final answer
   x = 1,248.97