Finding the Fourth Proportional to 42,939.30, 64,419.93 and 13,357.39

Step by Step Solution

1. Step 1: Write the proportion equation
   42,939.30 : 64,419.93 = 13,357.39 : x
2. Step 2: Convert to fraction form
   42,939.30/64,419.93 = 13,357.39/x
3. Step 3: Cross multiply
   42,939.30x = 64,419.93 × 13,357.39
4. Step 4: Simplify right side
   42,939.30x = 860,481,967.73
5. Step 5: Solve for x
   x = 860,481,967.73/42,939.30
6. Step 6: Final answer
   x = 20,039.50