Finding the Third Proportional to 10,909.69 and 12,987.84

Step by Step Solution

1. Step 1: Write the proportion equation
   10,909.69 : 12,987.84 = 12,987.84 : x
2. Step 2: Convert to fraction form
   10,909.69/12,987.84 = 12,987.84/x
3. Step 3: Cross multiply
   10,909.69x = 12,987.84 × 12,987.84
4. Step 4: Simplify right side
   10,909.69x = 168,684,085.27
5. Step 5: Solve for x
   x = 168,684,085.27/10,909.69
6. Step 6: Final answer
   x = 15,461.86