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Finding the Fourth Proportional to 330.72, 456.20 and 309.12

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Solution

The fourth proportional to 330.72, 456.20 and 309.12 is: 426.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    330.72 : 456.20 = 309.12 : x
  2. Step 2: Convert to fraction form
    330.72/456.20 = 309.12/x
  3. Step 3: Cross multiply
    330.72x = 456.20 × 309.12
  4. Step 4: Simplify right side
    330.72x = 141,020.54
  5. Step 5: Solve for x
    x = 141,020.54/330.72
  6. Step 6: Final answer
    x = 426.40

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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.