Finding the Fourth Proportional to 21,428, 29,570.76 and 13,976

Step by Step Solution

1. Step 1: Write the proportion equation
   21,428 : 29,570.76 = 13,976 : x
2. Step 2: Convert to fraction form
   21,428/29,570.76 = 13,976/x
3. Step 3: Cross multiply
   21,428x = 29,570.76 × 13,976
4. Step 4: Simplify right side
   21,428x = 413,280,941.76
5. Step 5: Solve for x
   x = 413,280,941.76/21,428
6. Step 6: Final answer
   x = 19,286.96