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Finding the Fourth Proportional to 87.12, 120.39 and 65.08

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Solution

The fourth proportional to 87.12, 120.39 and 65.08 is: 89.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.12 : 120.39 = 65.08 : x
  2. Step 2: Convert to fraction form
    87.12/120.39 = 65.08/x
  3. Step 3: Cross multiply
    87.12x = 120.39 × 65.08
  4. Step 4: Simplify right side
    87.12x = 7,834.89
  5. Step 5: Solve for x
    x = 7,834.89/87.12
  6. Step 6: Final answer
    x = 89.93

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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.