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Finding the Fourth Proportional to 318.70, 478.08 and 209.11

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Solution

The fourth proportional to 318.70, 478.08 and 209.11 is: 313.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.70 : 478.08 = 209.11 : x
  2. Step 2: Convert to fraction form
    318.70/478.08 = 209.11/x
  3. Step 3: Cross multiply
    318.70x = 478.08 × 209.11
  4. Step 4: Simplify right side
    318.70x = 99,971.31
  5. Step 5: Solve for x
    x = 99,971.31/318.70
  6. Step 6: Final answer
    x = 313.68

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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.