Finding the Fourth Proportional to 15,870.18, 21,900.53 and 9,155.63

Step by Step Solution

1. Step 1: Write the proportion equation
   15,870.18 : 21,900.53 = 9,155.63 : x
2. Step 2: Convert to fraction form
   15,870.18/21,900.53 = 9,155.63/x
3. Step 3: Cross multiply
   15,870.18x = 21,900.53 × 9,155.63
4. Step 4: Simplify right side
   15,870.18x = 200,513,175.62
5. Step 5: Solve for x
   x = 200,513,175.62/15,870.18
6. Step 6: Final answer
   x = 12,634.59