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Finding the Fourth Proportional to 206.99, 285.67 and 128.28

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Solution

The fourth proportional to 206.99, 285.67 and 128.28 is: 177.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.99 : 285.67 = 128.28 : x
  2. Step 2: Convert to fraction form
    206.99/285.67 = 128.28/x
  3. Step 3: Cross multiply
    206.99x = 285.67 × 128.28
  4. Step 4: Simplify right side
    206.99x = 36,646.98
  5. Step 5: Solve for x
    x = 36,646.98/206.99
  6. Step 6: Final answer
    x = 177.05

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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.