Finding the Fourth Proportional to 42,788.68, 64,129.50 and 20,596.12

Step by Step Solution

1. Step 1: Write the proportion equation
   42,788.68 : 64,129.50 = 20,596.12 : x
2. Step 2: Convert to fraction form
   42,788.68/64,129.50 = 20,596.12/x
3. Step 3: Cross multiply
   42,788.68x = 64,129.50 × 20,596.12
4. Step 4: Simplify right side
   42,788.68x = 1,320,818,877.54
5. Step 5: Solve for x
   x = 1,320,818,877.54/42,788.68
6. Step 6: Final answer
   x = 30,868.42