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Finding the Fourth Proportional to 52.20, 78.12 and 30.72

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Solution

The fourth proportional to 52.20, 78.12 and 30.72 is: 45.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    52.20 : 78.12 = 30.72 : x
  2. Step 2: Convert to fraction form
    52.20/78.12 = 30.72/x
  3. Step 3: Cross multiply
    52.20x = 78.12 × 30.72
  4. Step 4: Simplify right side
    52.20x = 2,399.85
  5. Step 5: Solve for x
    x = 2,399.85/52.20
  6. Step 6: Final answer
    x = 45.97

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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.