Finding the Fourth Proportional to 42,861.50, 64,333.82 and 20,690.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42,861.50 : 64,333.82 = 20,690.50 : x
2. Step 2: Convert to fraction form
   42,861.50/64,333.82 = 20,690.50/x
3. Step 3: Cross multiply
   42,861.50x = 64,333.82 × 20,690.50
4. Step 4: Simplify right side
   42,861.50x = 1,331,098,902.71
5. Step 5: Solve for x
   x = 1,331,098,902.71/42,861.50
6. Step 6: Final answer
   x = 31,055.82