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Finding the Fourth Proportional to 386.80, 533.78 and 209.76

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Solution

The fourth proportional to 386.80, 533.78 and 209.76 is: 289.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.80 : 533.78 = 209.76 : x
  2. Step 2: Convert to fraction form
    386.80/533.78 = 209.76/x
  3. Step 3: Cross multiply
    386.80x = 533.78 × 209.76
  4. Step 4: Simplify right side
    386.80x = 111,965.69
  5. Step 5: Solve for x
    x = 111,965.69/386.80
  6. Step 6: Final answer
    x = 289.47

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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.