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Finding the Fourth Proportional to 87.90, 131.30 and 69.81

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Solution

The fourth proportional to 87.90, 131.30 and 69.81 is: 104.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.90 : 131.30 = 69.81 : x
  2. Step 2: Convert to fraction form
    87.90/131.30 = 69.81/x
  3. Step 3: Cross multiply
    87.90x = 131.30 × 69.81
  4. Step 4: Simplify right side
    87.90x = 9,165.70
  5. Step 5: Solve for x
    x = 9,165.70/87.90
  6. Step 6: Final answer
    x = 104.27

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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.