Finding the Fourth Proportional to 1,142.54, 1,576.69 and 645.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.54 : 1,576.69 = 645.34 : x
2. Step 2: Convert to fraction form
   1,142.54/1,576.69 = 645.34/x
3. Step 3: Cross multiply
   1,142.54x = 1,576.69 × 645.34
4. Step 4: Simplify right side
   1,142.54x = 1,017,501.12
5. Step 5: Solve for x
   x = 1,017,501.12/1,142.54
6. Step 6: Final answer
   x = 890.56