Finding the Fourth Proportional to 12,961.68, 17,870.72 and 8,478.32

Step by Step Solution

1. Step 1: Write the proportion equation
   12,961.68 : 17,870.72 = 8,478.32 : x
2. Step 2: Convert to fraction form
   12,961.68/17,870.72 = 8,478.32/x
3. Step 3: Cross multiply
   12,961.68x = 17,870.72 × 8,478.32
4. Step 4: Simplify right side
   12,961.68x = 151,513,682.79
5. Step 5: Solve for x
   x = 151,513,682.79/12,961.68
6. Step 6: Final answer
   x = 11,689.36