Finding the Fourth Proportional to 42,699.28, 64,049.69 and 13,117.38

Step by Step Solution

1. Step 1: Write the proportion equation
   42,699.28 : 64,049.69 = 13,117.38 : x
2. Step 2: Convert to fraction form
   42,699.28/64,049.69 = 13,117.38/x
3. Step 3: Cross multiply
   42,699.28x = 64,049.69 × 13,117.38
4. Step 4: Simplify right side
   42,699.28x = 840,164,122.61
5. Step 5: Solve for x
   x = 840,164,122.61/42,699.28
6. Step 6: Final answer
   x = 19,676.31