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Finding the Fourth Proportional to 65.82, 90.78 and 39.96

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Solution

The fourth proportional to 65.82, 90.78 and 39.96 is: 55.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.82 : 90.78 = 39.96 : x
  2. Step 2: Convert to fraction form
    65.82/90.78 = 39.96/x
  3. Step 3: Cross multiply
    65.82x = 90.78 × 39.96
  4. Step 4: Simplify right side
    65.82x = 3,627.57
  5. Step 5: Solve for x
    x = 3,627.57/65.82
  6. Step 6: Final answer
    x = 55.11

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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.