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Finding the Third Proportional to 643.78 and 761.06

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Solution

The third proportional to 643.78 and 761.06 is: 899.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.78 : 761.06 = 761.06 : x
  2. Step 2: Convert to fraction form
    643.78/761.06 = 761.06/x
  3. Step 3: Cross multiply
    643.78x = 761.06 × 761.06
  4. Step 4: Simplify right side
    643.78x = 579,216.13
  5. Step 5: Solve for x
    x = 579,216.13/643.78
  6. Step 6: Final answer
    x = 899.71

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Why These Related Problems?

These problems maintain the same ratio (1.18) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.