Finding the Fourth Proportional to 20,978.35, 31,467.94 and 7,828.10

Step by Step Solution

1. Step 1: Write the proportion equation
   20,978.35 : 31,467.94 = 7,828.10 : x
2. Step 2: Convert to fraction form
   20,978.35/31,467.94 = 7,828.10/x
3. Step 3: Cross multiply
   20,978.35x = 31,467.94 × 7,828.10
4. Step 4: Simplify right side
   20,978.35x = 246,334,181.11
5. Step 5: Solve for x
   x = 246,334,181.11/20,978.35
6. Step 6: Final answer
   x = 11,742.30