Finding the Fourth Proportional to 42,856.53, 64,269.72 and 12,861.81

Step by Step Solution

1. Step 1: Write the proportion equation
   42,856.53 : 64,269.72 = 12,861.81 : x
2. Step 2: Convert to fraction form
   42,856.53/64,269.72 = 12,861.81/x
3. Step 3: Cross multiply
   42,856.53x = 64,269.72 × 12,861.81
4. Step 4: Simplify right side
   42,856.53x = 826,624,927.39
5. Step 5: Solve for x
   x = 826,624,927.39/42,856.53
6. Step 6: Final answer
   x = 19,288.19