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Finding the Fourth Proportional to 214.78, 322.17 and 77.81

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Solution

The fourth proportional to 214.78, 322.17 and 77.81 is: 116.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    214.78 : 322.17 = 77.81 : x
  2. Step 2: Convert to fraction form
    214.78/322.17 = 77.81/x
  3. Step 3: Cross multiply
    214.78x = 322.17 × 77.81
  4. Step 4: Simplify right side
    214.78x = 25,067.66
  5. Step 5: Solve for x
    x = 25,067.66/214.78
  6. Step 6: Final answer
    x = 116.72

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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.