Finding the Third Proportional to 6,421.50 and 13,690.50

Step by Step Solution

1. Step 1: Write the proportion equation
   6,421.50 : 13,690.50 = 13,690.50 : x
2. Step 2: Convert to fraction form
   6,421.50/13,690.50 = 13,690.50/x
3. Step 3: Cross multiply
   6,421.50x = 13,690.50 × 13,690.50
4. Step 4: Simplify right side
   6,421.50x = 187,429,790.25
5. Step 5: Solve for x
   x = 187,429,790.25/6,421.50
6. Step 6: Final answer
   x = 29,187.85