Finding the Third Proportional to 27,128.20 and 42,428.65

Step by Step Solution

1. Step 1: Write the proportion equation
   27,128.20 : 42,428.65 = 42,428.65 : x
2. Step 2: Convert to fraction form
   27,128.20/42,428.65 = 42,428.65/x
3. Step 3: Cross multiply
   27,128.20x = 42,428.65 × 42,428.65
4. Step 4: Simplify right side
   27,128.20x = 1,800,190,705.44
5. Step 5: Solve for x
   x = 1,800,190,705.44/27,128.20
6. Step 6: Final answer
   x = 66,358.66