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Finding the Fourth Proportional to 85.28, 117.55 and 55.72

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Solution

The fourth proportional to 85.28, 117.55 and 55.72 is: 76.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 117.55 = 55.72 : x
  2. Step 2: Convert to fraction form
    85.28/117.55 = 55.72/x
  3. Step 3: Cross multiply
    85.28x = 117.55 × 55.72
  4. Step 4: Simplify right side
    85.28x = 6,550.39
  5. Step 5: Solve for x
    x = 6,550.39/85.28
  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.