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Finding the Fourth Proportional to 39.84, 59.76 and 12.78

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Solution

The fourth proportional to 39.84, 59.76 and 12.78 is: 19.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.84 : 59.76 = 12.78 : x
  2. Step 2: Convert to fraction form
    39.84/59.76 = 12.78/x
  3. Step 3: Cross multiply
    39.84x = 59.76 × 12.78
  4. Step 4: Simplify right side
    39.84x = 763.81
  5. Step 5: Solve for x
    x = 763.81/39.84
  6. Step 6: Final answer
    x = 19.17

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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.