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Finding the Fourth Proportional to 61.79, 85.28 and 42.39

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Solution

The fourth proportional to 61.79, 85.28 and 42.39 is: 58.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.79 : 85.28 = 42.39 : x
  2. Step 2: Convert to fraction form
    61.79/85.28 = 42.39/x
  3. Step 3: Cross multiply
    61.79x = 85.28 × 42.39
  4. Step 4: Simplify right side
    61.79x = 3,614.81
  5. Step 5: Solve for x
    x = 3,614.81/61.79
  6. Step 6: Final answer
    x = 58.51

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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.