Finding the Fourth Proportional to 12,756.28, 17,612.43 and 7,978.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,756.28 : 17,612.43 = 7,978.30 : x
2. Step 2: Convert to fraction form
   12,756.28/17,612.43 = 7,978.30/x
3. Step 3: Cross multiply
   12,756.28x = 17,612.43 × 7,978.30
4. Step 4: Simplify right side
   12,756.28x = 140,517,250.27
5. Step 5: Solve for x
   x = 140,517,250.27/12,756.28
6. Step 6: Final answer
   x = 11,015.54