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Finding the Fourth Proportional to 405.78, 608.31 and 212.82

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Solution

The fourth proportional to 405.78, 608.31 and 212.82 is: 319.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.78 : 608.31 = 212.82 : x
  2. Step 2: Convert to fraction form
    405.78/608.31 = 212.82/x
  3. Step 3: Cross multiply
    405.78x = 608.31 × 212.82
  4. Step 4: Simplify right side
    405.78x = 129,460.53
  5. Step 5: Solve for x
    x = 129,460.53/405.78
  6. Step 6: Final answer
    x = 319.04

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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.