Finding the Third Proportional to 138.89 and 305.72

Step by Step Solution

1. Step 1: Write the proportion equation
   138.89 : 305.72 = 305.72 : x
2. Step 2: Convert to fraction form
   138.89/305.72 = 305.72/x
3. Step 3: Cross multiply
   138.89x = 305.72 × 305.72
4. Step 4: Simplify right side
   138.89x = 93,463.95
5. Step 5: Solve for x
   x = 93,463.95/138.89
6. Step 6: Final answer
   x = 672.93