Finding the Fourth Proportional to 42,728.86, 64,093.44 and 13,146.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42,728.86 : 64,093.44 = 13,146.50 : x
2. Step 2: Convert to fraction form
   42,728.86/64,093.44 = 13,146.50/x
3. Step 3: Cross multiply
   42,728.86x = 64,093.44 × 13,146.50
4. Step 4: Simplify right side
   42,728.86x = 842,604,408.96
5. Step 5: Solve for x
   x = 842,604,408.96/42,728.86
6. Step 6: Final answer
   x = 19,719.80