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Finding the Fourth Proportional to 85.82, 128.75 and 72.23

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Solution

The fourth proportional to 85.82, 128.75 and 72.23 is: 108.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.82 : 128.75 = 72.23 : x
  2. Step 2: Convert to fraction form
    85.82/128.75 = 72.23/x
  3. Step 3: Cross multiply
    85.82x = 128.75 × 72.23
  4. Step 4: Simplify right side
    85.82x = 9,298.61
  5. Step 5: Solve for x
    x = 9,298.61/85.82
  6. Step 6: Final answer
    x = 108.36

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.