Finding the Fourth Proportional to 1,645.75, 2,272.17 and 1,057.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,645.75 : 2,272.17 = 1,057.31 : x
2. Step 2: Convert to fraction form
   1,645.75/2,272.17 = 1,057.31/x
3. Step 3: Cross multiply
   1,645.75x = 2,272.17 × 1,057.31
4. Step 4: Simplify right side
   1,645.75x = 2,402,388.06
5. Step 5: Solve for x
   x = 2,402,388.06/1,645.75
6. Step 6: Final answer
   x = 1,459.75