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Finding the Fourth Proportional to 12.39, 18.59 and 4.78

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Solution

The fourth proportional to 12.39, 18.59 and 4.78 is: 7.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.39 : 18.59 = 4.78 : x
  2. Step 2: Convert to fraction form
    12.39/18.59 = 4.78/x
  3. Step 3: Cross multiply
    12.39x = 18.59 × 4.78
  4. Step 4: Simplify right side
    12.39x = 88.84
  5. Step 5: Solve for x
    x = 88.84/12.39
  6. Step 6: Final answer
    x = 7.17

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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.