Finding the Fourth Proportional to 9,913.21, 13,680.35 and 5,722.81

Step by Step Solution

1. Step 1: Write the proportion equation
   9,913.21 : 13,680.35 = 5,722.81 : x
2. Step 2: Convert to fraction form
   9,913.21/13,680.35 = 5,722.81/x
3. Step 3: Cross multiply
   9,913.21x = 13,680.35 × 5,722.81
4. Step 4: Simplify right side
   9,913.21x = 78,290,015.17
5. Step 5: Solve for x
   x = 78,290,015.17/9,913.21
6. Step 6: Final answer
   x = 7,897.54