Finding the Fourth Proportional to 9,620.90, 13,276.80 and 5,429.12

Step by Step Solution

1. Step 1: Write the proportion equation
   9,620.90 : 13,276.80 = 5,429.12 : x
2. Step 2: Convert to fraction form
   9,620.90/13,276.80 = 5,429.12/x
3. Step 3: Cross multiply
   9,620.90x = 13,276.80 × 5,429.12
4. Step 4: Simplify right side
   9,620.90x = 72,081,340.42
5. Step 5: Solve for x
   x = 72,081,340.42/9,620.90
6. Step 6: Final answer
   x = 7,492.16