Finding the Fourth Proportional to 39,978.96, 55,168.60 and 21,826.07

Step by Step Solution

1. Step 1: Write the proportion equation
   39,978.96 : 55,168.60 = 21,826.07 : x
2. Step 2: Convert to fraction form
   39,978.96/55,168.60 = 21,826.07/x
3. Step 3: Cross multiply
   39,978.96x = 55,168.60 × 21,826.07
4. Step 4: Simplify right side
   39,978.96x = 1,204,113,725.40
5. Step 5: Solve for x
   x = 1,204,113,725.40/39,978.96
6. Step 6: Final answer
   x = 30,118.69