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Finding the Fourth Proportional to 61.74, 85.16 and 39.88

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Solution

The fourth proportional to 61.74, 85.16 and 39.88 is: 55.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.74 : 85.16 = 39.88 : x
  2. Step 2: Convert to fraction form
    61.74/85.16 = 39.88/x
  3. Step 3: Cross multiply
    61.74x = 85.16 × 39.88
  4. Step 4: Simplify right side
    61.74x = 3,396.18
  5. Step 5: Solve for x
    x = 3,396.18/61.74
  6. Step 6: Final answer
    x = 55.01

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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.