Finding the Fourth Proportional to 28,734.74, 43,087.50 and 13,139

Step by Step Solution

1. Step 1: Write the proportion equation
   28,734.74 : 43,087.50 = 13,139 : x
2. Step 2: Convert to fraction form
   28,734.74/43,087.50 = 13,139/x
3. Step 3: Cross multiply
   28,734.74x = 43,087.50 × 13,139
4. Step 4: Simplify right side
   28,734.74x = 566,126,662.50
5. Step 5: Solve for x
   x = 566,126,662.50/28,734.74
6. Step 6: Final answer
   x = 19,701.82