Finding the Fourth Proportional to 9,139.35, 12,599.76 and 5,780.49

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.35 : 12,599.76 = 5,780.49 : x
2. Step 2: Convert to fraction form
   9,139.35/12,599.76 = 5,780.49/x
3. Step 3: Cross multiply
   9,139.35x = 12,599.76 × 5,780.49
4. Step 4: Simplify right side
   9,139.35x = 72,832,786.68
5. Step 5: Solve for x
   x = 72,832,786.68/9,139.35
6. Step 6: Final answer
   x = 7,969.14