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Finding the Fourth Proportional to 87.60, 120.60 and 65.43

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Solution

The fourth proportional to 87.60, 120.60 and 65.43 is: 90.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.60 : 120.60 = 65.43 : x
  2. Step 2: Convert to fraction form
    87.60/120.60 = 65.43/x
  3. Step 3: Cross multiply
    87.60x = 120.60 × 65.43
  4. Step 4: Simplify right side
    87.60x = 7,890.86
  5. Step 5: Solve for x
    x = 7,890.86/87.60
  6. Step 6: Final answer
    x = 90.08

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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.