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Finding the Fourth Proportional to 209.04, 311.28 and 206.78

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Solution

The fourth proportional to 209.04, 311.28 and 206.78 is: 307.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.04 : 311.28 = 206.78 : x
  2. Step 2: Convert to fraction form
    209.04/311.28 = 206.78/x
  3. Step 3: Cross multiply
    209.04x = 311.28 × 206.78
  4. Step 4: Simplify right side
    209.04x = 64,366.48
  5. Step 5: Solve for x
    x = 64,366.48/209.04
  6. Step 6: Final answer
    x = 307.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.