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Finding the Fourth Proportional to 318.20, 476.85 and 208.40

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Solution

The fourth proportional to 318.20, 476.85 and 208.40 is: 312.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.20 : 476.85 = 208.40 : x
  2. Step 2: Convert to fraction form
    318.20/476.85 = 208.40/x
  3. Step 3: Cross multiply
    318.20x = 476.85 × 208.40
  4. Step 4: Simplify right side
    318.20x = 99,375.54
  5. Step 5: Solve for x
    x = 99,375.54/318.20
  6. Step 6: Final answer
    x = 312.31

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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.