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Finding the Fourth Proportional to 256.70, 384.60 and 210.80

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Solution

The fourth proportional to 256.70, 384.60 and 210.80 is: 315.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.70 : 384.60 = 210.80 : x
  2. Step 2: Convert to fraction form
    256.70/384.60 = 210.80/x
  3. Step 3: Cross multiply
    256.70x = 384.60 × 210.80
  4. Step 4: Simplify right side
    256.70x = 81,073.68
  5. Step 5: Solve for x
    x = 81,073.68/256.70
  6. Step 6: Final answer
    x = 315.83

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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.