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Finding the Fourth Proportional to 256.72, 385.14 and 83.40

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Solution

The fourth proportional to 256.72, 385.14 and 83.40 is: 125.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.72 : 385.14 = 83.40 : x
  2. Step 2: Convert to fraction form
    256.72/385.14 = 83.40/x
  3. Step 3: Cross multiply
    256.72x = 385.14 × 83.40
  4. Step 4: Simplify right side
    256.72x = 32,119.08
  5. Step 5: Solve for x
    x = 32,119.08/256.72
  6. Step 6: Final answer
    x = 125.11

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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.