Finding the Fourth Proportional to 31,094.21, 42,876.14 and 21,005.15

Step by Step Solution

1. Step 1: Write the proportion equation
   31,094.21 : 42,876.14 = 21,005.15 : x
2. Step 2: Convert to fraction form
   31,094.21/42,876.14 = 21,005.15/x
3. Step 3: Cross multiply
   31,094.21x = 42,876.14 × 21,005.15
4. Step 4: Simplify right side
   31,094.21x = 900,619,432.71
5. Step 5: Solve for x
   x = 900,619,432.71/31,094.21
6. Step 6: Final answer
   x = 28,964.21