Finding the Fourth Proportional to 31,109.78, 42,931.51 and 17,680.69

Step by Step Solution

1. Step 1: Write the proportion equation
   31,109.78 : 42,931.51 = 17,680.69 : x
2. Step 2: Convert to fraction form
   31,109.78/42,931.51 = 17,680.69/x
3. Step 3: Cross multiply
   31,109.78x = 42,931.51 × 17,680.69
4. Step 4: Simplify right side
   31,109.78x = 759,058,719.54
5. Step 5: Solve for x
   x = 759,058,719.54/31,109.78
6. Step 6: Final answer
   x = 24,399.36