Finding the Fourth Proportional to 42,900.78, 64,352.88 and 13,317.96

Step by Step Solution

1. Step 1: Write the proportion equation
   42,900.78 : 64,352.88 = 13,317.96 : x
2. Step 2: Convert to fraction form
   42,900.78/64,352.88 = 13,317.96/x
3. Step 3: Cross multiply
   42,900.78x = 64,352.88 × 13,317.96
4. Step 4: Simplify right side
   42,900.78x = 857,049,081.72
5. Step 5: Solve for x
   x = 857,049,081.72/42,900.78
6. Step 6: Final answer
   x = 19,977.47