Finding the Third Proportional to 189,617 and 406,221

Step by Step Solution

1. Step 1: Write the proportion equation
   189,617 : 406,221 = 406,221 : x
2. Step 2: Convert to fraction form
   189,617/406,221 = 406,221/x
3. Step 3: Cross multiply
   189,617x = 406,221 × 406,221
4. Step 4: Simplify right side
   189,617x = 165,015,500,841
5. Step 5: Solve for x
   x = 165,015,500,841/189,617
6. Step 6: Final answer
   x = 870,256.89