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Finding the Fourth Proportional to 0.85, 1.28 and 0.71

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Solution

The fourth proportional to 0.85, 1.28 and 0.71 is: 1.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    0.85 : 1.28 = 0.71 : x
  2. Step 2: Convert to fraction form
    0.85/1.28 = 0.71/x
  3. Step 3: Cross multiply
    0.85x = 1.28 × 0.71
  4. Step 4: Simplify right side
    0.85x = 0.90
  5. Step 5: Solve for x
    x = 0.90/0.85
  6. Step 6: Final answer
    x = 1.06

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.