Finding the Fourth Proportional to 42,780, 64,195.92 and 18,156

Step by Step Solution

1. Step 1: Write the proportion equation
   42,780 : 64,195.92 = 18,156 : x
2. Step 2: Convert to fraction form
   42,780/64,195.92 = 18,156/x
3. Step 3: Cross multiply
   42,780x = 64,195.92 × 18,156
4. Step 4: Simplify right side
   42,780x = 1,165,541,123.52
5. Step 5: Solve for x
   x = 1,165,541,123.52/42,780
6. Step 6: Final answer
   x = 27,245.00