Finding the Fourth Proportional to 21,003.28, 28,971.70 and 12,499.69

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.28 : 28,971.70 = 12,499.69 : x
2. Step 2: Convert to fraction form
   21,003.28/28,971.70 = 12,499.69/x
3. Step 3: Cross multiply
   21,003.28x = 28,971.70 × 12,499.69
4. Step 4: Simplify right side
   21,003.28x = 362,137,268.77
5. Step 5: Solve for x
   x = 362,137,268.77/21,003.28
6. Step 6: Final answer
   x = 17,241.94