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Finding the Fourth Proportional to 442.40, 662.80 and 387.12

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Solution

The fourth proportional to 442.40, 662.80 and 387.12 is: 579.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    442.40 : 662.80 = 387.12 : x
  2. Step 2: Convert to fraction form
    442.40/662.80 = 387.12/x
  3. Step 3: Cross multiply
    442.40x = 662.80 × 387.12
  4. Step 4: Simplify right side
    442.40x = 256,583.14
  5. Step 5: Solve for x
    x = 256,583.14/442.40
  6. Step 6: Final answer
    x = 579.98

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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.