Finding the Fourth Proportional to 9,905.32, 13,668.78 and 5,428.18

Step by Step Solution

1. Step 1: Write the proportion equation
   9,905.32 : 13,668.78 = 5,428.18 : x
2. Step 2: Convert to fraction form
   9,905.32/13,668.78 = 5,428.18/x
3. Step 3: Cross multiply
   9,905.32x = 13,668.78 × 5,428.18
4. Step 4: Simplify right side
   9,905.32x = 74,196,598.22
5. Step 5: Solve for x
   x = 74,196,598.22/9,905.32
6. Step 6: Final answer
   x = 7,490.58