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Finding the Fourth Proportional to 107.70, 161.31 and 86.10

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Solution

The fourth proportional to 107.70, 161.31 and 86.10 is: 128.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.70 : 161.31 = 86.10 : x
  2. Step 2: Convert to fraction form
    107.70/161.31 = 86.10/x
  3. Step 3: Cross multiply
    107.70x = 161.31 × 86.10
  4. Step 4: Simplify right side
    107.70x = 13,888.79
  5. Step 5: Solve for x
    x = 13,888.79/107.70
  6. Step 6: Final answer
    x = 128.96

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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.