Finding the Fourth Proportional to 13,139.28, 18,131.50 and 7,473.28

Step by Step Solution

1. Step 1: Write the proportion equation
   13,139.28 : 18,131.50 = 7,473.28 : x
2. Step 2: Convert to fraction form
   13,139.28/18,131.50 = 7,473.28/x
3. Step 3: Cross multiply
   13,139.28x = 18,131.50 × 7,473.28
4. Step 4: Simplify right side
   13,139.28x = 135,501,776.32
5. Step 5: Solve for x
   x = 135,501,776.32/13,139.28
6. Step 6: Final answer
   x = 10,312.72