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Finding the Fourth Proportional to 61.80, 92.69 and 21.21

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Solution

The fourth proportional to 61.80, 92.69 and 21.21 is: 31.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.80 : 92.69 = 21.21 : x
  2. Step 2: Convert to fraction form
    61.80/92.69 = 21.21/x
  3. Step 3: Cross multiply
    61.80x = 92.69 × 21.21
  4. Step 4: Simplify right side
    61.80x = 1,965.85
  5. Step 5: Solve for x
    x = 1,965.85/61.80
  6. Step 6: Final answer
    x = 31.81

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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.