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Finding the Third Proportional to 645.75 and 915.75

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Solution

The third proportional to 645.75 and 915.75 is: 1,298.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.75 : 915.75 = 915.75 : x
  2. Step 2: Convert to fraction form
    645.75/915.75 = 915.75/x
  3. Step 3: Cross multiply
    645.75x = 915.75 × 915.75
  4. Step 4: Simplify right side
    645.75x = 838,598.06
  5. Step 5: Solve for x
    x = 838,598.06/645.75
  6. Step 6: Final answer
    x = 1,298.64

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Why These Related Problems?

These problems maintain the same ratio (1.42) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.