Finding the Fourth Proportional to 1,605.42, 2,215.52 and 906.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,605.42 : 2,215.52 = 906.80 : x
2. Step 2: Convert to fraction form
   1,605.42/2,215.52 = 906.80/x
3. Step 3: Cross multiply
   1,605.42x = 2,215.52 × 906.80
4. Step 4: Simplify right side
   1,605.42x = 2,009,022.46
5. Step 5: Solve for x
   x = 2,009,022.46/1,605.42
6. Step 6: Final answer
   x = 1,251.40