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Finding the Fourth Proportional to 442.40, 609.78 and 311.18

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Solution

The fourth proportional to 442.40, 609.78 and 311.18 is: 428.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    442.40 : 609.78 = 311.18 : x
  2. Step 2: Convert to fraction form
    442.40/609.78 = 311.18/x
  3. Step 3: Cross multiply
    442.40x = 609.78 × 311.18
  4. Step 4: Simplify right side
    442.40x = 189,751.34
  5. Step 5: Solve for x
    x = 189,751.34/442.40
  6. Step 6: Final answer
    x = 428.91

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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.