Finding the Fourth Proportional to 1,661.21, 2,290.43 and 1,345.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,661.21 : 2,290.43 = 1,345.31 : x
2. Step 2: Convert to fraction form
   1,661.21/2,290.43 = 1,345.31/x
3. Step 3: Cross multiply
   1,661.21x = 2,290.43 × 1,345.31
4. Step 4: Simplify right side
   1,661.21x = 3,081,331.32
5. Step 5: Solve for x
   x = 3,081,331.32/1,661.21
6. Step 6: Final answer
   x = 1,854.87