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Finding the Fourth Proportional to 257.20, 383.99 and 211.64

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Solution

The fourth proportional to 257.20, 383.99 and 211.64 is: 315.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.20 : 383.99 = 211.64 : x
  2. Step 2: Convert to fraction form
    257.20/383.99 = 211.64/x
  3. Step 3: Cross multiply
    257.20x = 383.99 × 211.64
  4. Step 4: Simplify right side
    257.20x = 81,264.67
  5. Step 5: Solve for x
    x = 81,264.67/257.20
  6. Step 6: Final answer
    x = 315.96

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.