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Finding the Fourth Proportional to 87.35, 120.42 and 74.21

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Solution

The fourth proportional to 87.35, 120.42 and 74.21 is: 102.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.35 : 120.42 = 74.21 : x
  2. Step 2: Convert to fraction form
    87.35/120.42 = 74.21/x
  3. Step 3: Cross multiply
    87.35x = 120.42 × 74.21
  4. Step 4: Simplify right side
    87.35x = 8,935.77
  5. Step 5: Solve for x
    x = 8,935.77/87.35
  6. Step 6: Final answer
    x = 102.30

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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.