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Finding the Fourth Proportional to 85.28, 127.38 and 71.60

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Solution

The fourth proportional to 85.28, 127.38 and 71.60 is: 106.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 127.38 = 71.60 : x
  2. Step 2: Convert to fraction form
    85.28/127.38 = 71.60/x
  3. Step 3: Cross multiply
    85.28x = 127.38 × 71.60
  4. Step 4: Simplify right side
    85.28x = 9,120.41
  5. Step 5: Solve for x
    x = 9,120.41/85.28
  6. Step 6: Final answer
    x = 106.95

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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.