Finding the Fourth Proportional to 1,139.28, 1,572.15 and 673.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.28 : 1,572.15 = 673.50 : x
2. Step 2: Convert to fraction form
   1,139.28/1,572.15 = 673.50/x
3. Step 3: Cross multiply
   1,139.28x = 1,572.15 × 673.50
4. Step 4: Simplify right side
   1,139.28x = 1,058,843.03
5. Step 5: Solve for x
   x = 1,058,843.03/1,139.28
6. Step 6: Final answer
   x = 929.40