Finding the Fourth Proportional to 1,142.50, 1,576.67 and 645.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.50 : 1,576.67 = 645.04 : x
2. Step 2: Convert to fraction form
   1,142.50/1,576.67 = 645.04/x
3. Step 3: Cross multiply
   1,142.50x = 1,576.67 × 645.04
4. Step 4: Simplify right side
   1,142.50x = 1,017,015.22
5. Step 5: Solve for x
   x = 1,017,015.22/1,142.50
6. Step 6: Final answer
   x = 890.17