Finding the Third Proportional to 15.56 and 42.09

Step by Step Solution

1. Step 1: Write the proportion equation
   15.56 : 42.09 = 42.09 : x
2. Step 2: Convert to fraction form
   15.56/42.09 = 42.09/x
3. Step 3: Cross multiply
   15.56x = 42.09 × 42.09
4. Step 4: Simplify right side
   15.56x = 1,771.88
5. Step 5: Solve for x
   x = 1,771.88/15.56
6. Step 6: Final answer
   x = 113.86