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Finding the Fourth Proportional to 61.80, 85.23 and 39.65

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Solution

The fourth proportional to 61.80, 85.23 and 39.65 is: 54.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.80 : 85.23 = 39.65 : x
  2. Step 2: Convert to fraction form
    61.80/85.23 = 39.65/x
  3. Step 3: Cross multiply
    61.80x = 85.23 × 39.65
  4. Step 4: Simplify right side
    61.80x = 3,379.37
  5. Step 5: Solve for x
    x = 3,379.37/61.80
  6. Step 6: Final answer
    x = 54.68

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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.