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Finding the Fourth Proportional to 85.76, 128.28 and 70.37

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Solution

The fourth proportional to 85.76, 128.28 and 70.37 is: 105.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.76 : 128.28 = 70.37 : x
  2. Step 2: Convert to fraction form
    85.76/128.28 = 70.37/x
  3. Step 3: Cross multiply
    85.76x = 128.28 × 70.37
  4. Step 4: Simplify right side
    85.76x = 9,027.17
  5. Step 5: Solve for x
    x = 9,027.17/85.76
  6. Step 6: Final answer
    x = 105.26

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.