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Finding the Third Proportional to 643.78 and 1,397.67

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Solution

The third proportional to 643.78 and 1,397.67 is: 3,034.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.78 : 1,397.67 = 1,397.67 : x
  2. Step 2: Convert to fraction form
    643.78/1,397.67 = 1,397.67/x
  3. Step 3: Cross multiply
    643.78x = 1,397.67 × 1,397.67
  4. Step 4: Simplify right side
    643.78x = 1,953,486.67
  5. Step 5: Solve for x
    x = 1,953,486.67/643.78
  6. Step 6: Final answer
    x = 3,034.40

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Why These Related Problems?

These problems maintain the same ratio (2.17) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.