Finding the Fourth Proportional to 42,815.45, 64,229.32 and 13,235.59

Step by Step Solution

1. Step 1: Write the proportion equation
   42,815.45 : 64,229.32 = 13,235.59 : x
2. Step 2: Convert to fraction form
   42,815.45/64,229.32 = 13,235.59/x
3. Step 3: Cross multiply
   42,815.45x = 64,229.32 × 13,235.59
4. Step 4: Simplify right side
   42,815.45x = 850,112,979.93
5. Step 5: Solve for x
   x = 850,112,979.93/42,815.45
6. Step 6: Final answer
   x = 19,855.29