Finding the Third Proportional to 20.42 and 42.99

Step by Step Solution

1. Step 1: Write the proportion equation
   20.42 : 42.99 = 42.99 : x
2. Step 2: Convert to fraction form
   20.42/42.99 = 42.99/x
3. Step 3: Cross multiply
   20.42x = 42.99 × 42.99
4. Step 4: Simplify right side
   20.42x = 1,848.33
5. Step 5: Solve for x
   x = 1,848.33/20.42
6. Step 6: Final answer
   x = 90.51