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Finding the Fourth Proportional to 330.78, 456.40 and 206.40

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Solution

The fourth proportional to 330.78, 456.40 and 206.40 is: 284.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    330.78 : 456.40 = 206.40 : x
  2. Step 2: Convert to fraction form
    330.78/456.40 = 206.40/x
  3. Step 3: Cross multiply
    330.78x = 456.40 × 206.40
  4. Step 4: Simplify right side
    330.78x = 94,200.96
  5. Step 5: Solve for x
    x = 94,200.96/330.78
  6. Step 6: Final answer
    x = 284.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.