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Finding the Fourth Proportional to 318.12, 438.60 and 281.20

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Solution

The fourth proportional to 318.12, 438.60 and 281.20 is: 387.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.12 : 438.60 = 281.20 : x
  2. Step 2: Convert to fraction form
    318.12/438.60 = 281.20/x
  3. Step 3: Cross multiply
    318.12x = 438.60 × 281.20
  4. Step 4: Simplify right side
    318.12x = 123,334.32
  5. Step 5: Solve for x
    x = 123,334.32/318.12
  6. Step 6: Final answer
    x = 387.70

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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.