Finding the Fourth Proportional to 1,142.33, 1,576.55 and 645.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.33 : 1,576.55 = 645.05 : x
2. Step 2: Convert to fraction form
   1,142.33/1,576.55 = 645.05/x
3. Step 3: Cross multiply
   1,142.33x = 1,576.55 × 645.05
4. Step 4: Simplify right side
   1,142.33x = 1,016,959.13
5. Step 5: Solve for x
   x = 1,016,959.13/1,142.33
6. Step 6: Final answer
   x = 890.25