Finding the Fourth Proportional to 1,070.72, 1,605.62 and 411.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,070.72 : 1,605.62 = 411.89 : x
2. Step 2: Convert to fraction form
   1,070.72/1,605.62 = 411.89/x
3. Step 3: Cross multiply
   1,070.72x = 1,605.62 × 411.89
4. Step 4: Simplify right side
   1,070.72x = 661,331.82
5. Step 5: Solve for x
   x = 661,331.82/1,070.72
6. Step 6: Final answer
   x = 617.65