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Finding the Fourth Proportional to 87.21, 120.35 and 61.02

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Solution

The fourth proportional to 87.21, 120.35 and 61.02 is: 84.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.21 : 120.35 = 61.02 : x
  2. Step 2: Convert to fraction form
    87.21/120.35 = 61.02/x
  3. Step 3: Cross multiply
    87.21x = 120.35 × 61.02
  4. Step 4: Simplify right side
    87.21x = 7,343.76
  5. Step 5: Solve for x
    x = 7,343.76/87.21
  6. Step 6: Final answer
    x = 84.21

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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.