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Finding the Fourth Proportional to 64.85, 89.49 and 39.97

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Solution

The fourth proportional to 64.85, 89.49 and 39.97 is: 55.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.85 : 89.49 = 39.97 : x
  2. Step 2: Convert to fraction form
    64.85/89.49 = 39.97/x
  3. Step 3: Cross multiply
    64.85x = 89.49 × 39.97
  4. Step 4: Simplify right side
    64.85x = 3,576.92
  5. Step 5: Solve for x
    x = 3,576.92/64.85
  6. Step 6: Final answer
    x = 55.16

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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.