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Finding the Third Proportional to 840 and 1,211.81

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Solution

The third proportional to 840 and 1,211.81 is: 1,748.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    840 : 1,211.81 = 1,211.81 : x
  2. Step 2: Convert to fraction form
    840/1,211.81 = 1,211.81/x
  3. Step 3: Cross multiply
    840x = 1,211.81 × 1,211.81
  4. Step 4: Simplify right side
    840x = 1,468,489.54
  5. Step 5: Solve for x
    x = 1,468,489.54/840
  6. Step 6: Final answer
    x = 1,748.20

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Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.