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Finding the Fourth Proportional to 61.77, 85.21 and 39.67

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Solution

The fourth proportional to 61.77, 85.21 and 39.67 is: 54.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.77 : 85.21 = 39.67 : x
  2. Step 2: Convert to fraction form
    61.77/85.21 = 39.67/x
  3. Step 3: Cross multiply
    61.77x = 85.21 × 39.67
  4. Step 4: Simplify right side
    61.77x = 3,379.85
  5. Step 5: Solve for x
    x = 3,379.85/61.77
  6. Step 6: Final answer
    x = 54.72

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.