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Finding the Third Proportional to 645 and 715

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Solution

The third proportional to 645 and 715 is: 792.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    645 : 715 = 715 : x
  2. Step 2: Convert to fraction form
    645/715 = 715/x
  3. Step 3: Cross multiply
    645x = 715 × 715
  4. Step 4: Simplify right side
    645x = 511,225
  5. Step 5: Solve for x
    x = 511,225/645
  6. Step 6: Final answer
    x = 792.60

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Why These Related Problems?

These problems maintain the same ratio (1.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.