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Finding the Fourth Proportional to 64.08, 87.87 and 61.78

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Solution

The fourth proportional to 64.08, 87.87 and 61.78 is: 84.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.08 : 87.87 = 61.78 : x
  2. Step 2: Convert to fraction form
    64.08/87.87 = 61.78/x
  3. Step 3: Cross multiply
    64.08x = 87.87 × 61.78
  4. Step 4: Simplify right side
    64.08x = 5,428.61
  5. Step 5: Solve for x
    x = 5,428.61/64.08
  6. Step 6: Final answer
    x = 84.72

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.