Finding the Fourth Proportional to 31,047.21, 42,895.34 and 21,657.69

Step by Step Solution

1. Step 1: Write the proportion equation
   31,047.21 : 42,895.34 = 21,657.69 : x
2. Step 2: Convert to fraction form
   31,047.21/42,895.34 = 21,657.69/x
3. Step 3: Cross multiply
   31,047.21x = 42,895.34 × 21,657.69
4. Step 4: Simplify right side
   31,047.21x = 929,013,867.88
5. Step 5: Solve for x
   x = 929,013,867.88/31,047.21
6. Step 6: Final answer
   x = 29,922.62