Finding the Fourth Proportional to 15,507.48, 21,407.67 and 9,921.72

Step by Step Solution

1. Step 1: Write the proportion equation
   15,507.48 : 21,407.67 = 9,921.72 : x
2. Step 2: Convert to fraction form
   15,507.48/21,407.67 = 9,921.72/x
3. Step 3: Cross multiply
   15,507.48x = 21,407.67 × 9,921.72
4. Step 4: Simplify right side
   15,507.48x = 212,400,907.59
5. Step 5: Solve for x
   x = 212,400,907.59/15,507.48
6. Step 6: Final answer
   x = 13,696.67