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Finding the Fourth Proportional to 85.84, 128.70 and 30.97

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Solution

The fourth proportional to 85.84, 128.70 and 30.97 is: 46.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.84 : 128.70 = 30.97 : x
  2. Step 2: Convert to fraction form
    85.84/128.70 = 30.97/x
  3. Step 3: Cross multiply
    85.84x = 128.70 × 30.97
  4. Step 4: Simplify right side
    85.84x = 3,986.00
  5. Step 5: Solve for x
    x = 3,986.00/85.84
  6. Step 6: Final answer
    x = 46.44

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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.