Finding the Fourth Proportional to 14,215.12, 21,308.91 and 7,978.12

Step by Step Solution

1. Step 1: Write the proportion equation
   14,215.12 : 21,308.91 = 7,978.12 : x
2. Step 2: Convert to fraction form
   14,215.12/21,308.91 = 7,978.12/x
3. Step 3: Cross multiply
   14,215.12x = 21,308.91 × 7,978.12
4. Step 4: Simplify right side
   14,215.12x = 170,005,041.05
5. Step 5: Solve for x
   x = 170,005,041.05/14,215.12
6. Step 6: Final answer
   x = 11,959.45