Finding the Third Proportional to 1,069.17 and 1,221.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,069.17 : 1,221.05 = 1,221.05 : x
2. Step 2: Convert to fraction form
   1,069.17/1,221.05 = 1,221.05/x
3. Step 3: Cross multiply
   1,069.17x = 1,221.05 × 1,221.05
4. Step 4: Simplify right side
   1,069.17x = 1,490,955.47
5. Step 5: Solve for x
   x = 1,490,955.47/1,069.17
6. Step 6: Final answer
   x = 1,394.50