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Finding the Fourth Proportional to 85.12, 127.16 and 78.28

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Solution

The fourth proportional to 85.12, 127.16 and 78.28 is: 116.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.12 : 127.16 = 78.28 : x
  2. Step 2: Convert to fraction form
    85.12/127.16 = 78.28/x
  3. Step 3: Cross multiply
    85.12x = 127.16 × 78.28
  4. Step 4: Simplify right side
    85.12x = 9,954.08
  5. Step 5: Solve for x
    x = 9,954.08/85.12
  6. Step 6: Final answer
    x = 116.94

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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.