Finding the Fourth Proportional to 1,007.32, 1,390.18 and 559.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.32 : 1,390.18 = 559.21 : x
2. Step 2: Convert to fraction form
   1,007.32/1,390.18 = 559.21/x
3. Step 3: Cross multiply
   1,007.32x = 1,390.18 × 559.21
4. Step 4: Simplify right side
   1,007.32x = 777,399.76
5. Step 5: Solve for x
   x = 777,399.76/1,007.32
6. Step 6: Final answer
   x = 771.75