Finding the Fourth Proportional to 1,015.56, 1,522.99 and 399.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,015.56 : 1,522.99 = 399.10 : x
2. Step 2: Convert to fraction form
   1,015.56/1,522.99 = 399.10/x
3. Step 3: Cross multiply
   1,015.56x = 1,522.99 × 399.10
4. Step 4: Simplify right side
   1,015.56x = 607,825.31
5. Step 5: Solve for x
   x = 607,825.31/1,015.56
6. Step 6: Final answer
   x = 598.51