Finding the Fourth Proportional to 1,345.78, 2,019.59 and 480.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.78 : 2,019.59 = 480.09 : x
2. Step 2: Convert to fraction form
   1,345.78/2,019.59 = 480.09/x
3. Step 3: Cross multiply
   1,345.78x = 2,019.59 × 480.09
4. Step 4: Simplify right side
   1,345.78x = 969,591.94
5. Step 5: Solve for x
   x = 969,591.94/1,345.78
6. Step 6: Final answer
   x = 720.47