Finding the Fourth Proportional to 1,406.88, 2,109.72 and 432.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,406.88 : 2,109.72 = 432.72 : x
2. Step 2: Convert to fraction form
   1,406.88/2,109.72 = 432.72/x
3. Step 3: Cross multiply
   1,406.88x = 2,109.72 × 432.72
4. Step 4: Simplify right side
   1,406.88x = 912,918.04
5. Step 5: Solve for x
   x = 912,918.04/1,406.88
6. Step 6: Final answer
   x = 648.90