Finding the Fourth Proportional to 21,005.69, 31,456.83 and 13,587.44

Step by Step Solution

1. Step 1: Write the proportion equation
   21,005.69 : 31,456.83 = 13,587.44 : x
2. Step 2: Convert to fraction form
   21,005.69/31,456.83 = 13,587.44/x
3. Step 3: Cross multiply
   21,005.69x = 31,456.83 × 13,587.44
4. Step 4: Simplify right side
   21,005.69x = 427,417,790.22
5. Step 5: Solve for x
   x = 427,417,790.22/21,005.69
6. Step 6: Final answer
   x = 20,347.71