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Finding the Fourth Proportional to 256.30, 384.45 and 215.80

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Solution

The fourth proportional to 256.30, 384.45 and 215.80 is: 323.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.30 : 384.45 = 215.80 : x
  2. Step 2: Convert to fraction form
    256.30/384.45 = 215.80/x
  3. Step 3: Cross multiply
    256.30x = 384.45 × 215.80
  4. Step 4: Simplify right side
    256.30x = 82,964.31
  5. Step 5: Solve for x
    x = 82,964.31/256.30
  6. Step 6: Final answer
    x = 323.70

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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.