Finding the Fourth Proportional to 28,109.19, 42,168.36 and 13,131.29

Step by Step Solution

1. Step 1: Write the proportion equation
   28,109.19 : 42,168.36 = 13,131.29 : x
2. Step 2: Convert to fraction form
   28,109.19/42,168.36 = 13,131.29/x
3. Step 3: Cross multiply
   28,109.19x = 42,168.36 × 13,131.29
4. Step 4: Simplify right side
   28,109.19x = 553,724,753.14
5. Step 5: Solve for x
   x = 553,724,753.14/28,109.19
6. Step 6: Final answer
   x = 19,699.06