Finding the Fourth Proportional to 31,080.34, 42,876.14 and 21,012.24

Step by Step Solution

1. Step 1: Write the proportion equation
   31,080.34 : 42,876.14 = 21,012.24 : x
2. Step 2: Convert to fraction form
   31,080.34/42,876.14 = 21,012.24/x
3. Step 3: Cross multiply
   31,080.34x = 42,876.14 × 21,012.24
4. Step 4: Simplify right side
   31,080.34x = 900,923,799.68
5. Step 5: Solve for x
   x = 900,923,799.68/31,080.34
6. Step 6: Final answer
   x = 28,986.93