Finding the Fourth Proportional to 9,315.72, 12,855.80 and 5,124

Step by Step Solution

1. Step 1: Write the proportion equation
   9,315.72 : 12,855.80 = 5,124 : x
2. Step 2: Convert to fraction form
   9,315.72/12,855.80 = 5,124/x
3. Step 3: Cross multiply
   9,315.72x = 12,855.80 × 5,124
4. Step 4: Simplify right side
   9,315.72x = 65,873,119.20
5. Step 5: Solve for x
   x = 65,873,119.20/9,315.72
6. Step 6: Final answer
   x = 7,071.18