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Finding the Third Proportional to 643.13 and 1,386.19

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Solution

The third proportional to 643.13 and 1,386.19 is: 2,987.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.13 : 1,386.19 = 1,386.19 : x
  2. Step 2: Convert to fraction form
    643.13/1,386.19 = 1,386.19/x
  3. Step 3: Cross multiply
    643.13x = 1,386.19 × 1,386.19
  4. Step 4: Simplify right side
    643.13x = 1,921,515.79
  5. Step 5: Solve for x
    x = 1,921,515.79/643.13
  6. Step 6: Final answer
    x = 2,987.78

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Why These Related Problems?

These problems maintain the same ratio (2.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.