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Finding the Fourth Proportional to 102.70, 142.06 and 86.30

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Solution

The fourth proportional to 102.70, 142.06 and 86.30 is: 119.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.70 : 142.06 = 86.30 : x
  2. Step 2: Convert to fraction form
    102.70/142.06 = 86.30/x
  3. Step 3: Cross multiply
    102.70x = 142.06 × 86.30
  4. Step 4: Simplify right side
    102.70x = 12,259.78
  5. Step 5: Solve for x
    x = 12,259.78/102.70
  6. Step 6: Final answer
    x = 119.37

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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.