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Finding the Fourth Proportional to 85.38, 117.72 and 69.81

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Solution

The fourth proportional to 85.38, 117.72 and 69.81 is: 96.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.38 : 117.72 = 69.81 : x
  2. Step 2: Convert to fraction form
    85.38/117.72 = 69.81/x
  3. Step 3: Cross multiply
    85.38x = 117.72 × 69.81
  4. Step 4: Simplify right side
    85.38x = 8,217.66
  5. Step 5: Solve for x
    x = 8,217.66/85.38
  6. Step 6: Final answer
    x = 96.25

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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.