Finding the Fourth Proportional to 31,079.22, 42,875.67 and 21,003.99

Step by Step Solution

1. Step 1: Write the proportion equation
   31,079.22 : 42,875.67 = 21,003.99 : x
2. Step 2: Convert to fraction form
   31,079.22/42,875.67 = 21,003.99/x
3. Step 3: Cross multiply
   31,079.22x = 42,875.67 × 21,003.99
4. Step 4: Simplify right side
   31,079.22x = 900,560,143.92
5. Step 5: Solve for x
   x = 900,560,143.92/31,079.22
6. Step 6: Final answer
   x = 28,976.28