Finding the Fourth Proportional to 31,020.21, 42,784.94 and 19,679.91

Step by Step Solution

1. Step 1: Write the proportion equation
   31,020.21 : 42,784.94 = 19,679.91 : x
2. Step 2: Convert to fraction form
   31,020.21/42,784.94 = 19,679.91/x
3. Step 3: Cross multiply
   31,020.21x = 42,784.94 × 19,679.91
4. Step 4: Simplify right side
   31,020.21x = 842,003,670.16
5. Step 5: Solve for x
   x = 842,003,670.16/31,020.21
6. Step 6: Final answer
   x = 27,143.71