Finding the Fourth Proportional to 1,139.52, 1,572.54 and 673.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.52 : 1,572.54 = 673.80 : x
2. Step 2: Convert to fraction form
   1,139.52/1,572.54 = 673.80/x
3. Step 3: Cross multiply
   1,139.52x = 1,572.54 × 673.80
4. Step 4: Simplify right side
   1,139.52x = 1,059,577.45
5. Step 5: Solve for x
   x = 1,059,577.45/1,139.52
6. Step 6: Final answer
   x = 929.85