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Finding the Fourth Proportional to 104.40, 155.75 and 86.31

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Solution

The fourth proportional to 104.40, 155.75 and 86.31 is: 128.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.40 : 155.75 = 86.31 : x
  2. Step 2: Convert to fraction form
    104.40/155.75 = 86.31/x
  3. Step 3: Cross multiply
    104.40x = 155.75 × 86.31
  4. Step 4: Simplify right side
    104.40x = 13,442.35
  5. Step 5: Solve for x
    x = 13,442.35/104.40
  6. Step 6: Final answer
    x = 128.76

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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.