Finding the Third Proportional to 66.50 and 99.69

Step by Step Solution

1. Step 1: Write the proportion equation
   66.50 : 99.69 = 99.69 : x
2. Step 2: Convert to fraction form
   66.50/99.69 = 99.69/x
3. Step 3: Cross multiply
   66.50x = 99.69 × 99.69
4. Step 4: Simplify right side
   66.50x = 9,937.60
5. Step 5: Solve for x
   x = 9,937.60/66.50
6. Step 6: Final answer
   x = 149.44