Finding the Third Proportional to 65,638.69 and 72,405.56

Step by Step Solution

1. Step 1: Write the proportion equation
   65,638.69 : 72,405.56 = 72,405.56 : x
2. Step 2: Convert to fraction form
   65,638.69/72,405.56 = 72,405.56/x
3. Step 3: Cross multiply
   65,638.69x = 72,405.56 × 72,405.56
4. Step 4: Simplify right side
   65,638.69x = 5,242,565,480.94
5. Step 5: Solve for x
   x = 5,242,565,480.94/65,638.69
6. Step 6: Final answer
   x = 79,870.05