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Finding the Fourth Proportional to 85.12, 117.48 and 55.65

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Solution

The fourth proportional to 85.12, 117.48 and 55.65 is: 76.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.12 : 117.48 = 55.65 : x
  2. Step 2: Convert to fraction form
    85.12/117.48 = 55.65/x
  3. Step 3: Cross multiply
    85.12x = 117.48 × 55.65
  4. Step 4: Simplify right side
    85.12x = 6,537.76
  5. Step 5: Solve for x
    x = 6,537.76/85.12
  6. Step 6: Final answer
    x = 76.81

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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.