Finding the Fourth Proportional to 1,139.16, 1,707.28 and 522.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.16 : 1,707.28 = 522.72 : x
2. Step 2: Convert to fraction form
   1,139.16/1,707.28 = 522.72/x
3. Step 3: Cross multiply
   1,139.16x = 1,707.28 × 522.72
4. Step 4: Simplify right side
   1,139.16x = 892,429.40
5. Step 5: Solve for x
   x = 892,429.40/1,139.16
6. Step 6: Final answer
   x = 783.41