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Finding the Fourth Proportional to 78.28, 107.89 and 65.14

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Solution

The fourth proportional to 78.28, 107.89 and 65.14 is: 89.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.28 : 107.89 = 65.14 : x
  2. Step 2: Convert to fraction form
    78.28/107.89 = 65.14/x
  3. Step 3: Cross multiply
    78.28x = 107.89 × 65.14
  4. Step 4: Simplify right side
    78.28x = 7,027.52
  5. Step 5: Solve for x
    x = 7,027.52/78.28
  6. Step 6: Final answer
    x = 89.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.