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Finding the Fourth Proportional to 85.44, 127.68 and 77.28

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Solution

The fourth proportional to 85.44, 127.68 and 77.28 is: 115.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.44 : 127.68 = 77.28 : x
  2. Step 2: Convert to fraction form
    85.44/127.68 = 77.28/x
  3. Step 3: Cross multiply
    85.44x = 127.68 × 77.28
  4. Step 4: Simplify right side
    85.44x = 9,867.11
  5. Step 5: Solve for x
    x = 9,867.11/85.44
  6. Step 6: Final answer
    x = 115.49

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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.