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Finding the Fourth Proportional to 256.25, 384.42 and 85.25

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Solution

The fourth proportional to 256.25, 384.42 and 85.25 is: 127.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.25 : 384.42 = 85.25 : x
  2. Step 2: Convert to fraction form
    256.25/384.42 = 85.25/x
  3. Step 3: Cross multiply
    256.25x = 384.42 × 85.25
  4. Step 4: Simplify right side
    256.25x = 32,771.81
  5. Step 5: Solve for x
    x = 32,771.81/256.25
  6. Step 6: Final answer
    x = 127.89

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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.