Finding the Fourth Proportional to 21,987.57, 30,342.87 and 13,039.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,987.57 : 30,342.87 = 13,039.50 : x
2. Step 2: Convert to fraction form
   21,987.57/30,342.87 = 13,039.50/x
3. Step 3: Cross multiply
   21,987.57x = 30,342.87 × 13,039.50
4. Step 4: Simplify right side
   21,987.57x = 395,655,853.37
5. Step 5: Solve for x
   x = 395,655,853.37/21,987.57
6. Step 6: Final answer
   x = 17,994.52