Finding the Fourth Proportional to 42,979.08, 64,468.64 and 13,399.30

Step by Step Solution

1. Step 1: Write the proportion equation
   42,979.08 : 64,468.64 = 13,399.30 : x
2. Step 2: Convert to fraction form
   42,979.08/64,468.64 = 13,399.30/x
3. Step 3: Cross multiply
   42,979.08x = 64,468.64 × 13,399.30
4. Step 4: Simplify right side
   42,979.08x = 863,834,647.95
5. Step 5: Solve for x
   x = 863,834,647.95/42,979.08
6. Step 6: Final answer
   x = 20,098.96