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Finding the Fourth Proportional to 84.15, 116.20 and 65.81

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Solution

The fourth proportional to 84.15, 116.20 and 65.81 is: 90.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.15 : 116.20 = 65.81 : x
  2. Step 2: Convert to fraction form
    84.15/116.20 = 65.81/x
  3. Step 3: Cross multiply
    84.15x = 116.20 × 65.81
  4. Step 4: Simplify right side
    84.15x = 7,647.49
  5. Step 5: Solve for x
    x = 7,647.49/84.15
  6. Step 6: Final answer
    x = 90.88

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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.