Finding the Third Proportional to 8,558.63 and 12,780.56

Step by Step Solution

1. Step 1: Write the proportion equation
   8,558.63 : 12,780.56 = 12,780.56 : x
2. Step 2: Convert to fraction form
   8,558.63/12,780.56 = 12,780.56/x
3. Step 3: Cross multiply
   8,558.63x = 12,780.56 × 12,780.56
4. Step 4: Simplify right side
   8,558.63x = 163,342,777.82
5. Step 5: Solve for x
   x = 163,342,777.82/8,558.63
6. Step 6: Final answer
   x = 19,085.17