Finding the Fourth Proportional to 980.83, 1,353.78 and 561.42

Step by Step Solution

1. Step 1: Write the proportion equation
   980.83 : 1,353.78 = 561.42 : x
2. Step 2: Convert to fraction form
   980.83/1,353.78 = 561.42/x
3. Step 3: Cross multiply
   980.83x = 1,353.78 × 561.42
4. Step 4: Simplify right side
   980.83x = 760,039.18
5. Step 5: Solve for x
   x = 760,039.18/980.83
6. Step 6: Final answer
   x = 774.90