Finding the Fourth Proportional to 9,905.80, 13,669.50 and 5,428.76

Step by Step Solution

1. Step 1: Write the proportion equation
   9,905.80 : 13,669.50 = 5,428.76 : x
2. Step 2: Convert to fraction form
   9,905.80/13,669.50 = 5,428.76/x
3. Step 3: Cross multiply
   9,905.80x = 13,669.50 × 5,428.76
4. Step 4: Simplify right side
   9,905.80x = 74,208,434.82
5. Step 5: Solve for x
   x = 74,208,434.82/9,905.80
6. Step 6: Final answer
   x = 7,491.41