Finding the Fourth Proportional to 31,072.10, 42,865.83 and 20,996.87

Step by Step Solution

1. Step 1: Write the proportion equation
   31,072.10 : 42,865.83 = 20,996.87 : x
2. Step 2: Convert to fraction form
   31,072.10/42,865.83 = 20,996.87/x
3. Step 3: Cross multiply
   31,072.10x = 42,865.83 × 20,996.87
4. Step 4: Simplify right side
   31,072.10x = 900,048,045.62
5. Step 5: Solve for x
   x = 900,048,045.62/31,072.10
6. Step 6: Final answer
   x = 28,966.44