Finding the Fourth Proportional to 1,047.20, 1,569.17 and 430.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,047.20 : 1,569.17 = 430.72 : x
2. Step 2: Convert to fraction form
   1,047.20/1,569.17 = 430.72/x
3. Step 3: Cross multiply
   1,047.20x = 1,569.17 × 430.72
4. Step 4: Simplify right side
   1,047.20x = 675,870.06
5. Step 5: Solve for x
   x = 675,870.06/1,047.20
6. Step 6: Final answer
   x = 645.41