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Finding the Fourth Proportional to 84.78, 117 and 55.70

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Solution

The fourth proportional to 84.78, 117 and 55.70 is: 76.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.78 : 117 = 55.70 : x
  2. Step 2: Convert to fraction form
    84.78/117 = 55.70/x
  3. Step 3: Cross multiply
    84.78x = 117 × 55.70
  4. Step 4: Simplify right side
    84.78x = 6,516.90
  5. Step 5: Solve for x
    x = 6,516.90/84.78
  6. Step 6: Final answer
    x = 76.87

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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.