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Finding the Fourth Proportional to 85.21, 126.85 and 84.70

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Solution

The fourth proportional to 85.21, 126.85 and 84.70 is: 126.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.21 : 126.85 = 84.70 : x
  2. Step 2: Convert to fraction form
    85.21/126.85 = 84.70/x
  3. Step 3: Cross multiply
    85.21x = 126.85 × 84.70
  4. Step 4: Simplify right side
    85.21x = 10,744.20
  5. Step 5: Solve for x
    x = 10,744.20/85.21
  6. Step 6: Final answer
    x = 126.09

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.