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Finding the Fourth Proportional to 386.17, 579.22 and 212.78

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Solution

The fourth proportional to 386.17, 579.22 and 212.78 is: 319.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.17 : 579.22 = 212.78 : x
  2. Step 2: Convert to fraction form
    386.17/579.22 = 212.78/x
  3. Step 3: Cross multiply
    386.17x = 579.22 × 212.78
  4. Step 4: Simplify right side
    386.17x = 123,246.43
  5. Step 5: Solve for x
    x = 123,246.43/386.17
  6. Step 6: Final answer
    x = 319.15

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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.