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Finding the Fourth Proportional to 86,478, 129,717 and 20,814

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Solution

The fourth proportional to 86,478, 129,717 and 20,814 is: 31,221

Step by Step Solution

  1. Step 1: Write the proportion equation
    86,478 : 129,717 = 20,814 : x
  2. Step 2: Convert to fraction form
    86,478/129,717 = 20,814/x
  3. Step 3: Cross multiply
    86,478x = 129,717 × 20,814
  4. Step 4: Simplify right side
    86,478x = 2,699,929,638
  5. Step 5: Solve for x
    x = 2,699,929,638/86,478
  6. Step 6: Final answer
    x = 31,221

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.