Finding the Third Proportional to 121.50 and 131.88

Step by Step Solution

1. Step 1: Write the proportion equation
   121.50 : 131.88 = 131.88 : x
2. Step 2: Convert to fraction form
   121.50/131.88 = 131.88/x
3. Step 3: Cross multiply
   121.50x = 131.88 × 131.88
4. Step 4: Simplify right side
   121.50x = 17,391.02
5. Step 5: Solve for x
   x = 17,391.02/121.50
6. Step 6: Final answer
   x = 143.14