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Finding the Third Proportional to 781.21 and 1,211.20

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Solution

The third proportional to 781.21 and 1,211.20 is: 1,877.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.21 : 1,211.20 = 1,211.20 : x
  2. Step 2: Convert to fraction form
    781.21/1,211.20 = 1,211.20/x
  3. Step 3: Cross multiply
    781.21x = 1,211.20 × 1,211.20
  4. Step 4: Simplify right side
    781.21x = 1,467,013.01
  5. Step 5: Solve for x
    x = 1,467,013.01/781.21
  6. Step 6: Final answer
    x = 1,877.88

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Why These Related Problems?

These problems maintain the same ratio (1.55) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.