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Finding the Fourth Proportional to 52.78, 79.18 and 20.72

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Solution

The fourth proportional to 52.78, 79.18 and 20.72 is: 31.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    52.78 : 79.18 = 20.72 : x
  2. Step 2: Convert to fraction form
    52.78/79.18 = 20.72/x
  3. Step 3: Cross multiply
    52.78x = 79.18 × 20.72
  4. Step 4: Simplify right side
    52.78x = 1,640.61
  5. Step 5: Solve for x
    x = 1,640.61/52.78
  6. Step 6: Final answer
    x = 31.08

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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.