Finding the Fourth Proportional to 7,320.84, 10,978.56 and 5,128.44

Step by Step Solution

1. Step 1: Write the proportion equation
   7,320.84 : 10,978.56 = 5,128.44 : x
2. Step 2: Convert to fraction form
   7,320.84/10,978.56 = 5,128.44/x
3. Step 3: Cross multiply
   7,320.84x = 10,978.56 × 5,128.44
4. Step 4: Simplify right side
   7,320.84x = 56,302,886.25
5. Step 5: Solve for x
   x = 56,302,886.25/7,320.84
6. Step 6: Final answer
   x = 7,690.77