Finding the Fourth Proportional to 42,810.17, 64,187.91 and 20,579.31

Step by Step Solution

1. Step 1: Write the proportion equation
   42,810.17 : 64,187.91 = 20,579.31 : x
2. Step 2: Convert to fraction form
   42,810.17/64,187.91 = 20,579.31/x
3. Step 3: Cross multiply
   42,810.17x = 64,187.91 × 20,579.31
4. Step 4: Simplify right side
   42,810.17x = 1,320,942,898.14
5. Step 5: Solve for x
   x = 1,320,942,898.14/42,810.17
6. Step 6: Final answer
   x = 30,855.82