Finding the Fourth Proportional to 1,152.10, 1,728.38 and 421.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,152.10 : 1,728.38 = 421.59 : x
2. Step 2: Convert to fraction form
   1,152.10/1,728.38 = 421.59/x
3. Step 3: Cross multiply
   1,152.10x = 1,728.38 × 421.59
4. Step 4: Simplify right side
   1,152.10x = 728,667.72
5. Step 5: Solve for x
   x = 728,667.72/1,152.10
6. Step 6: Final answer
   x = 632.47