Finding the Fourth Proportional to 1,428.05, 1,970.57 and 904.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.05 : 1,970.57 = 904.07 : x
2. Step 2: Convert to fraction form
   1,428.05/1,970.57 = 904.07/x
3. Step 3: Cross multiply
   1,428.05x = 1,970.57 × 904.07
4. Step 4: Simplify right side
   1,428.05x = 1,781,525.63
5. Step 5: Solve for x
   x = 1,781,525.63/1,428.05
6. Step 6: Final answer
   x = 1,247.53