Finding the Fourth Proportional to 9,912.56, 13,679.22 and 5,720.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,912.56 : 13,679.22 = 5,720.72 : x
2. Step 2: Convert to fraction form
   9,912.56/13,679.22 = 5,720.72/x
3. Step 3: Cross multiply
   9,912.56x = 13,679.22 × 5,720.72
4. Step 4: Simplify right side
   9,912.56x = 78,254,987.44
5. Step 5: Solve for x
   x = 78,254,987.44/9,912.56
6. Step 6: Final answer
   x = 7,894.53