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Finding the Fourth Proportional to 87.16, 131 and 72.80

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Solution

The fourth proportional to 87.16, 131 and 72.80 is: 109.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.16 : 131 = 72.80 : x
  2. Step 2: Convert to fraction form
    87.16/131 = 72.80/x
  3. Step 3: Cross multiply
    87.16x = 131 × 72.80
  4. Step 4: Simplify right side
    87.16x = 9,536.80
  5. Step 5: Solve for x
    x = 9,536.80/87.16
  6. Step 6: Final answer
    x = 109.42

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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.