Finding the Fourth Proportional to 1,389.02, 2,082.31 and 522.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.02 : 2,082.31 = 522.72 : x
2. Step 2: Convert to fraction form
   1,389.02/2,082.31 = 522.72/x
3. Step 3: Cross multiply
   1,389.02x = 2,082.31 × 522.72
4. Step 4: Simplify right side
   1,389.02x = 1,088,462.47
5. Step 5: Solve for x
   x = 1,088,462.47/1,389.02
6. Step 6: Final answer
   x = 783.62