Finding the Fourth Proportional to 28,429.63, 42,609.86 and 20,112.05

Step by Step Solution

1. Step 1: Write the proportion equation
   28,429.63 : 42,609.86 = 20,112.05 : x
2. Step 2: Convert to fraction form
   28,429.63/42,609.86 = 20,112.05/x
3. Step 3: Cross multiply
   28,429.63x = 42,609.86 × 20,112.05
4. Step 4: Simplify right side
   28,429.63x = 856,971,321.20
5. Step 5: Solve for x
   x = 856,971,321.20/28,429.63
6. Step 6: Final answer
   x = 30,143.60