Finding the Fourth Proportional to 20,820.42, 28,741.56 and 13,276.89

Step by Step Solution

1. Step 1: Write the proportion equation
   20,820.42 : 28,741.56 = 13,276.89 : x
2. Step 2: Convert to fraction form
   20,820.42/28,741.56 = 13,276.89/x
3. Step 3: Cross multiply
   20,820.42x = 28,741.56 × 13,276.89
4. Step 4: Simplify right side
   20,820.42x = 381,598,530.55
5. Step 5: Solve for x
   x = 381,598,530.55/20,820.42
6. Step 6: Final answer
   x = 18,328.09