Finding the Fourth Proportional to 31,119.12, 42,910.36 and 21,030.05

Step by Step Solution

1. Step 1: Write the proportion equation
   31,119.12 : 42,910.36 = 21,030.05 : x
2. Step 2: Convert to fraction form
   31,119.12/42,910.36 = 21,030.05/x
3. Step 3: Cross multiply
   31,119.12x = 42,910.36 × 21,030.05
4. Step 4: Simplify right side
   31,119.12x = 902,407,071.02
5. Step 5: Solve for x
   x = 902,407,071.02/31,119.12
6. Step 6: Final answer
   x = 28,998.48