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Finding the Fourth Proportional to 51.18, 77 and 30.91

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Solution

The fourth proportional to 51.18, 77 and 30.91 is: 46.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    51.18 : 77 = 30.91 : x
  2. Step 2: Convert to fraction form
    51.18/77 = 30.91/x
  3. Step 3: Cross multiply
    51.18x = 77 × 30.91
  4. Step 4: Simplify right side
    51.18x = 2,379.69
  5. Step 5: Solve for x
    x = 2,379.69/51.18
  6. Step 6: Final answer
    x = 46.50

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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.