Finding the Fourth Proportional to 42,690.55, 64,045.34 and 13,111.38

Step by Step Solution

1. Step 1: Write the proportion equation
   42,690.55 : 64,045.34 = 13,111.38 : x
2. Step 2: Convert to fraction form
   42,690.55/64,045.34 = 13,111.38/x
3. Step 3: Cross multiply
   42,690.55x = 64,045.34 × 13,111.38
4. Step 4: Simplify right side
   42,690.55x = 839,722,789.97
5. Step 5: Solve for x
   x = 839,722,789.97/42,690.55
6. Step 6: Final answer
   x = 19,669.99