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Finding the Fourth Proportional to 61.15, 84.30 and 42.70

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Solution

The fourth proportional to 61.15, 84.30 and 42.70 is: 58.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.15 : 84.30 = 42.70 : x
  2. Step 2: Convert to fraction form
    61.15/84.30 = 42.70/x
  3. Step 3: Cross multiply
    61.15x = 84.30 × 42.70
  4. Step 4: Simplify right side
    61.15x = 3,599.61
  5. Step 5: Solve for x
    x = 3,599.61/61.15
  6. Step 6: Final answer
    x = 58.87

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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.