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Finding the Fourth Proportional to 85.76, 127.78 and 84.56

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Solution

The fourth proportional to 85.76, 127.78 and 84.56 is: 125.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.76 : 127.78 = 84.56 : x
  2. Step 2: Convert to fraction form
    85.76/127.78 = 84.56/x
  3. Step 3: Cross multiply
    85.76x = 127.78 × 84.56
  4. Step 4: Simplify right side
    85.76x = 10,805.08
  5. Step 5: Solve for x
    x = 10,805.08/85.76
  6. Step 6: Final answer
    x = 125.99

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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.