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Finding the Fourth Proportional to 85.38, 117.89 and 66

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Solution

The fourth proportional to 85.38, 117.89 and 66 is: 91.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.38 : 117.89 = 66 : x
  2. Step 2: Convert to fraction form
    85.38/117.89 = 66/x
  3. Step 3: Cross multiply
    85.38x = 117.89 × 66
  4. Step 4: Simplify right side
    85.38x = 7,780.74
  5. Step 5: Solve for x
    x = 7,780.74/85.38
  6. Step 6: Final answer
    x = 91.13

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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.