Finding the Fourth Proportional to 1,142.94, 1,577.12 and 645.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.94 : 1,577.12 = 645.59 : x
2. Step 2: Convert to fraction form
   1,142.94/1,577.12 = 645.59/x
3. Step 3: Cross multiply
   1,142.94x = 1,577.12 × 645.59
4. Step 4: Simplify right side
   1,142.94x = 1,018,161.79
5. Step 5: Solve for x
   x = 1,018,161.79/1,142.94
6. Step 6: Final answer
   x = 890.83