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Finding the Fourth Proportional to 87.15, 130.82 and 78.54

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Solution

The fourth proportional to 87.15, 130.82 and 78.54 is: 117.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.15 : 130.82 = 78.54 : x
  2. Step 2: Convert to fraction form
    87.15/130.82 = 78.54/x
  3. Step 3: Cross multiply
    87.15x = 130.82 × 78.54
  4. Step 4: Simplify right side
    87.15x = 10,274.21
  5. Step 5: Solve for x
    x = 10,274.21/87.15
  6. Step 6: Final answer
    x = 117.89

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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.