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Finding the Fourth Proportional to 87.60, 131.40 and 64.80

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Solution

The fourth proportional to 87.60, 131.40 and 64.80 is: 97.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.60 : 131.40 = 64.80 : x
  2. Step 2: Convert to fraction form
    87.60/131.40 = 64.80/x
  3. Step 3: Cross multiply
    87.60x = 131.40 × 64.80
  4. Step 4: Simplify right side
    87.60x = 8,514.72
  5. Step 5: Solve for x
    x = 8,514.72/87.60
  6. Step 6: Final answer
    x = 97.20

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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.