Finding the Fourth Proportional to 42,889.46, 64,377.76 and 20,721.48

Step by Step Solution

1. Step 1: Write the proportion equation
   42,889.46 : 64,377.76 = 20,721.48 : x
2. Step 2: Convert to fraction form
   42,889.46/64,377.76 = 20,721.48/x
3. Step 3: Cross multiply
   42,889.46x = 64,377.76 × 20,721.48
4. Step 4: Simplify right side
   42,889.46x = 1,334,002,722.85
5. Step 5: Solve for x
   x = 1,334,002,722.85/42,889.46
6. Step 6: Final answer
   x = 31,103.27