Finding the Fourth Proportional to 12,978.16, 17,908.78 and 7,311.10

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.16 : 17,908.78 = 7,311.10 : x
2. Step 2: Convert to fraction form
   12,978.16/17,908.78 = 7,311.10/x
3. Step 3: Cross multiply
   12,978.16x = 17,908.78 × 7,311.10
4. Step 4: Simplify right side
   12,978.16x = 130,932,881.46
5. Step 5: Solve for x
   x = 130,932,881.46/12,978.16
6. Step 6: Final answer
   x = 10,088.71