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Finding the Fourth Proportional to 61.76, 85.28 and 40.79

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Solution

The fourth proportional to 61.76, 85.28 and 40.79 is: 56.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.76 : 85.28 = 40.79 : x
  2. Step 2: Convert to fraction form
    61.76/85.28 = 40.79/x
  3. Step 3: Cross multiply
    61.76x = 85.28 × 40.79
  4. Step 4: Simplify right side
    61.76x = 3,478.58
  5. Step 5: Solve for x
    x = 3,478.58/61.76
  6. Step 6: Final answer
    x = 56.32

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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.