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Finding the Fourth Proportional to 79.20, 109.28 and 49.68

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Solution

The fourth proportional to 79.20, 109.28 and 49.68 is: 68.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.20 : 109.28 = 49.68 : x
  2. Step 2: Convert to fraction form
    79.20/109.28 = 49.68/x
  3. Step 3: Cross multiply
    79.20x = 109.28 × 49.68
  4. Step 4: Simplify right side
    79.20x = 5,429.03
  5. Step 5: Solve for x
    x = 5,429.03/79.20
  6. Step 6: Final answer
    x = 68.55

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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.