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Finding the Fourth Proportional to 85.68, 117.72 and 84.36

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Solution

The fourth proportional to 85.68, 117.72 and 84.36 is: 115.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.68 : 117.72 = 84.36 : x
  2. Step 2: Convert to fraction form
    85.68/117.72 = 84.36/x
  3. Step 3: Cross multiply
    85.68x = 117.72 × 84.36
  4. Step 4: Simplify right side
    85.68x = 9,930.86
  5. Step 5: Solve for x
    x = 9,930.86/85.68
  6. Step 6: Final answer
    x = 115.91

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.