Finding the Fourth Proportional to 10,665.51, 15,991.40 and 4,429.82

Step by Step Solution

1. Step 1: Write the proportion equation
   10,665.51 : 15,991.40 = 4,429.82 : x
2. Step 2: Convert to fraction form
   10,665.51/15,991.40 = 4,429.82/x
3. Step 3: Cross multiply
   10,665.51x = 15,991.40 × 4,429.82
4. Step 4: Simplify right side
   10,665.51x = 70,839,023.55
5. Step 5: Solve for x
   x = 70,839,023.55/10,665.51
6. Step 6: Final answer
   x = 6,641.88