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Finding the Third Proportional to 678.66 and 905.91

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Solution

The third proportional to 678.66 and 905.91 is: 1,209.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.66 : 905.91 = 905.91 : x
  2. Step 2: Convert to fraction form
    678.66/905.91 = 905.91/x
  3. Step 3: Cross multiply
    678.66x = 905.91 × 905.91
  4. Step 4: Simplify right side
    678.66x = 820,666.13
  5. Step 5: Solve for x
    x = 820,666.13/678.66
  6. Step 6: Final answer
    x = 1,209.25

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Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.