Finding the Fourth Proportional to 42,789.27, 64,185.72 and 13,206.45

Step by Step Solution

1. Step 1: Write the proportion equation
   42,789.27 : 64,185.72 = 13,206.45 : x
2. Step 2: Convert to fraction form
   42,789.27/64,185.72 = 13,206.45/x
3. Step 3: Cross multiply
   42,789.27x = 64,185.72 × 13,206.45
4. Step 4: Simplify right side
   42,789.27x = 847,665,501.89
5. Step 5: Solve for x
   x = 847,665,501.89/42,789.27
6. Step 6: Final answer
   x = 19,810.24