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Finding the Fourth Proportional to 51.72, 77.62 and 21.28

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Solution

The fourth proportional to 51.72, 77.62 and 21.28 is: 31.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.72 : 77.62 = 21.28 : x
  2. Step 2: Convert to fraction form
    51.72/77.62 = 21.28/x
  3. Step 3: Cross multiply
    51.72x = 77.62 × 21.28
  4. Step 4: Simplify right side
    51.72x = 1,651.75
  5. Step 5: Solve for x
    x = 1,651.75/51.72
  6. Step 6: Final answer
    x = 31.94

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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.