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Finding the Fourth Proportional to 258.64, 387.96 and 87.64

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Solution

The fourth proportional to 258.64, 387.96 and 87.64 is: 131.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.64 : 387.96 = 87.64 : x
  2. Step 2: Convert to fraction form
    258.64/387.96 = 87.64/x
  3. Step 3: Cross multiply
    258.64x = 387.96 × 87.64
  4. Step 4: Simplify right side
    258.64x = 34,000.81
  5. Step 5: Solve for x
    x = 34,000.81/258.64
  6. Step 6: Final answer
    x = 131.46

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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.