Finding the Fourth Proportional to 42,686.55, 64,039.34 and 13,107.38

Step by Step Solution

1. Step 1: Write the proportion equation
   42,686.55 : 64,039.34 = 13,107.38 : x
2. Step 2: Convert to fraction form
   42,686.55/64,039.34 = 13,107.38/x
3. Step 3: Cross multiply
   42,686.55x = 64,039.34 × 13,107.38
4. Step 4: Simplify right side
   42,686.55x = 839,387,578.60
5. Step 5: Solve for x
   x = 839,387,578.60/42,686.55
6. Step 6: Final answer
   x = 19,663.98