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Finding the Fourth Proportional to 51.38, 77.02 and 20.91

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Solution

The fourth proportional to 51.38, 77.02 and 20.91 is: 31.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.38 : 77.02 = 20.91 : x
  2. Step 2: Convert to fraction form
    51.38/77.02 = 20.91/x
  3. Step 3: Cross multiply
    51.38x = 77.02 × 20.91
  4. Step 4: Simplify right side
    51.38x = 1,610.72
  5. Step 5: Solve for x
    x = 1,610.72/51.38
  6. Step 6: Final answer
    x = 31.35

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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.