Finding the Fourth Proportional to 9,907.50, 14,863.72 and 6,991.50

Step by Step Solution

1. Step 1: Write the proportion equation
   9,907.50 : 14,863.72 = 6,991.50 : x
2. Step 2: Convert to fraction form
   9,907.50/14,863.72 = 6,991.50/x
3. Step 3: Cross multiply
   9,907.50x = 14,863.72 × 6,991.50
4. Step 4: Simplify right side
   9,907.50x = 103,919,698.38
5. Step 5: Solve for x
   x = 103,919,698.38/9,907.50
6. Step 6: Final answer
   x = 10,488.99