Finding the Fourth Proportional to 31,164.48, 42,990.48 and 21,079.68

Step by Step Solution

1. Step 1: Write the proportion equation
   31,164.48 : 42,990.48 = 21,079.68 : x
2. Step 2: Convert to fraction form
   31,164.48/42,990.48 = 21,079.68/x
3. Step 3: Cross multiply
   31,164.48x = 42,990.48 × 21,079.68
4. Step 4: Simplify right side
   31,164.48x = 906,225,561.45
5. Step 5: Solve for x
   x = 906,225,561.45/31,164.48
6. Step 6: Final answer
   x = 29,078.80