Finding the Fourth Proportional to 1,142.82, 1,576.98 and 645.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.82 : 1,576.98 = 645.39 : x
2. Step 2: Convert to fraction form
   1,142.82/1,576.98 = 645.39/x
3. Step 3: Cross multiply
   1,142.82x = 1,576.98 × 645.39
4. Step 4: Simplify right side
   1,142.82x = 1,017,767.12
5. Step 5: Solve for x
   x = 1,017,767.12/1,142.82
6. Step 6: Final answer
   x = 890.58