Finding the Third Proportional to 66.38 and 143.72

Step by Step Solution

1. Step 1: Write the proportion equation
   66.38 : 143.72 = 143.72 : x
2. Step 2: Convert to fraction form
   66.38/143.72 = 143.72/x
3. Step 3: Cross multiply
   66.38x = 143.72 × 143.72
4. Step 4: Simplify right side
   66.38x = 20,655.08
5. Step 5: Solve for x
   x = 20,655.08/66.38
6. Step 6: Final answer
   x = 311.19