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Finding the Third Proportional to 489.80 and 689.13

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Solution

The third proportional to 489.80 and 689.13 is: 969.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.80 : 689.13 = 689.13 : x
  2. Step 2: Convert to fraction form
    489.80/689.13 = 689.13/x
  3. Step 3: Cross multiply
    489.80x = 689.13 × 689.13
  4. Step 4: Simplify right side
    489.80x = 474,904.03
  5. Step 5: Solve for x
    x = 474,904.03/489.80
  6. Step 6: Final answer
    x = 969.59

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Why These Related Problems?

These problems maintain the same ratio (1.41) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.