Finding the Fourth Proportional to 28,561.13, 42,869.37 and 13,780.42

Step by Step Solution

1. Step 1: Write the proportion equation
   28,561.13 : 42,869.37 = 13,780.42 : x
2. Step 2: Convert to fraction form
   28,561.13/42,869.37 = 13,780.42/x
3. Step 3: Cross multiply
   28,561.13x = 42,869.37 × 13,780.42
4. Step 4: Simplify right side
   28,561.13x = 590,757,923.74
5. Step 5: Solve for x
   x = 590,757,923.74/28,561.13
6. Step 6: Final answer
   x = 20,683.98