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Finding the Fourth Proportional to 87.39, 120.69 and 74.32

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Solution

The fourth proportional to 87.39, 120.69 and 74.32 is: 102.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.39 : 120.69 = 74.32 : x
  2. Step 2: Convert to fraction form
    87.39/120.69 = 74.32/x
  3. Step 3: Cross multiply
    87.39x = 120.69 × 74.32
  4. Step 4: Simplify right side
    87.39x = 8,969.68
  5. Step 5: Solve for x
    x = 8,969.68/87.39
  6. Step 6: Final answer
    x = 102.64

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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.