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Finding the Third Proportional to 345.09 and 689.91

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Solution

The third proportional to 345.09 and 689.91 is: 1,379.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    345.09 : 689.91 = 689.91 : x
  2. Step 2: Convert to fraction form
    345.09/689.91 = 689.91/x
  3. Step 3: Cross multiply
    345.09x = 689.91 × 689.91
  4. Step 4: Simplify right side
    345.09x = 475,970.63
  5. Step 5: Solve for x
    x = 475,970.63/345.09
  6. Step 6: Final answer
    x = 1,379.25

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Why These Related Problems?

These problems maintain the same ratio (2.00) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.