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Finding the Fourth Proportional to 30.69, 42.39 and 29.79

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Solution

The fourth proportional to 30.69, 42.39 and 29.79 is: 41.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.69 : 42.39 = 29.79 : x
  2. Step 2: Convert to fraction form
    30.69/42.39 = 29.79/x
  3. Step 3: Cross multiply
    30.69x = 42.39 × 29.79
  4. Step 4: Simplify right side
    30.69x = 1,262.80
  5. Step 5: Solve for x
    x = 1,262.80/30.69
  6. Step 6: Final answer
    x = 41.15

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.